Hard Gold Plating PCB

  • Excellent for high-wear products
  • Durable and hard surface
  • Long Shelf life
  •  RoHS Compliant

Venture – Your Expert Hard Gold Plating PCB Manufacturer in China

hard gold plating pcb

If you`re looking for a durable Hard Gold Plating PCB, always count on Venture. Venture has been engaged in the production of hard gold plating PCB manufacturing for more than 10 years and has accumulated profound industry experience. Owing to our experience, we developed the ability to provide comprehensive and quality solutions according to the actual situations and as per the needs of various customers worldwide.

At Venture, you can get hard gold plating PCB with many competitive advantages and is widely used in this field. Our hard gold plating PCB  most commonly applied to high-wear areas such as keypads and gold fingers. It is extremely durable, with RoHS Compliant.

As a reliable manufacturer in China, we have a strong sense of service. We provide easy access to customers, materials, workers, transportation, and so on. You can save time and reduce costs here in Venture!

Reputable Hard Gold Plating PCB Manufacturer in China

hard gold plating pcb

As a professional PCB manufacturer in China, you can depend on Venture when you are sourcing for a Hard gold plating PCB. We are committed to providing the most promising quality Hard gold plating PCB at a very competitive price.

Hard gold plating PCB with the full name of Electrolytic Nickel Electrolytic Gold consists of a layer of gold plated over a barrier coat of nickel. It is commonly applied in high-wear areas such as edge connectors or gold fingers and keypads. It may also be plated over the entire circuit boards.

hard gold plating pcb

Using high-tech machinery and high-quality raw materials, Venture carefully-designed hard gold plating PCB with many advantages. We manufacture it durable with a hard surface. This has a long shelf life and attracts users’ attention with its easy-to-use performance.

At Venture, we are capable of using hard gold plated on both entire PCB and gold fingers, the typical thickness of hard gold plated on the entire board is 0.1 – 1.27um and the typical thickness of hard gold plated for gold fingers can be 0.1 – 3.0um.

Venture Electronics, is a professional PCB manufacturing company in China that produces and supplies a broad range of products. With more than 10 years of history and development, we are dedicated to delivering the best quality products at the best price. Our team provides unparalleled customer service. That’s why we established a good relationship with many clients throughout the world. Will you be the next?

hard gold plating pcb

Of course, we are your turnkey solution provider since 2010. Venture Electronics is built to meet customer support, owing to our strong marketing and technical support team. Committed to improving prototyping through production processes for the design engineer from quote to delivery, from PCB design & layout, PCB fabrication, and PCB turnkey assembly.

Not only Hard Gold Plating PCB. We also provide a wide range of products inapplicable for many applications including countersink PCB, aluminum nitride PCB, USB flash drive PCB, Long Aluminum LED PCB and many others. All products are compliant with RoHS.

For all types of PCB-related products in all quantities, you can rely on Venture Electronics. We are happy to serve you. Contact us today.

Hard Gold Plating PCB: The Ultimate FAQs Guide

Hard Gold Plating PCB The Ultimate FAQs Guide

Also known as hard electrolytic gold, hard gold plating PCB constitutes a gold layer plated above a barrier nickel coat.

Hard gold plating is exceptionally durable therefore PCB manufacturers normally apply it to high-wear sections like keypads and gold fingers.

Why Should You Choose Hard Gold Plating PCB?

Hard Gold Plating PCB

Hard Gold Plating PCB

The common benefits of selecting hard gold-plated PCB comprise of:

  • Electrical Conductivity

In terms of electrical conductivity, gold (21.4 nΩ*m) comes third after copper and silver. Nonetheless, it maintains its electrical conductivity way better compared to copper and silver even under tough conditions through prolonged timespan.

Due to this fact, most PCB surface finish operation use PCB gold plating to guarantee a constant and dependable conductive path.

  • Thermal Conductivity

With respect to thermal conductivity, gold (315 W/m*K) also come third after silver and copper. It maintains its high thermal conductivity even in severe applications because gold doesn’t develop insulating oxides/compounds on its surface.

Owing to this fact, uses of hard gold plating PCB involve employing them in down-hole drilling and outer space applications.

  • Ductility

Gold is an exceptionally ductile metal, a feature that makes it perfect for flexible PCB contacts. The ductility of hard gold plating PCB makes it endure recurrent contact cycles.

However, it is essential to remember that correct selection and application of underplate is crucial. This ensures that the hard gold PCB surface finish satisfies the design specifications for gold plated PCB contacts or connectors.

  • Non-Reactivity

PCB Gold plating doesn’t react or develop compounds when in contact with other elements. It is this unique feature of gold plating PCB that makes it corrosion resistant.

  • Corrosion Resistance

Gold has great corrosion resistance even under severe conditions due to its unreactive nature. This makes hard gold plating PCB perfect for applications involving corrosive environments.

  • Non-Hazardous

You can safely place hard gold-plated PCB in human body without worrying about biocompatibility.

  • Visual Appeal

Hard electrolytic gold plating PCB enhances the appearance of your circuit board. The PCB surface finish does not easily oxidize or tarnish so long as the gold thickness is adequate.

What Is The Difference Between Full Body Vs. Selective Hard Gold Plating PCB?

Full body PCB hard gold plating is typically a rarely-selected PCB surface finish. Here, you plate the entire circuit board body using hard gold.

To perform full body hard gold plating, you use an electrolytic procedure or immersion operation based on PCB design. However, you need to factor in that hard gold plating PCB has poor solderability. This means you will need an extremely active flux to solder efficiently to the circuit board pad.

Selective hard gold PCB plating entails utilizing hard gold to plate particular sections on a printed circuit board. The process of applying selective gold is almost similar to full body hard gold.

Selective Hard Gold Plated PCB

Selective Hard Gold Plated PCB

Nevertheless, the selective gold plating process needs some masking. This will incur extra labour expenses, compensated by reduced hard gold plating PCB material cost.

Which Is Better Between ENIG Vs. Hard Gold Plating PCB Finishes?

There are two main design options when you need PCB gold plating finishes: ENIG plating and hard gold plating.

Hard gold PCB plating entails polished grain surface and firm deposits from the gold, usually alloyed with nickel.

Conversely, electroless nickel immersion gold, ENIG plating closely resembles pure gold since it involves no other elements. This makes it softer in comparison to PCB hard gold plating.

  • Hard Gold Plating

Hard gold plating PCB generally includes the tinniest grain sizes possible, which span 20-30 nanometers, with hardness in 130 to 200 HK25 range.

These features make hard gold finish way more lustrous compared to PCB ENIG plating.

It also implies that hard gold plating is highly effective in preventing sliding wear. The PCB surface finish can endure applications that exert 50g or more of contact force.

Furthermore, hard gold plating PCB can manage way more cycles in comparison to ENIG plating PCB.

However, the precise number of cycles rely on the PCB plating thickness.

The main disadvantage of hard gold plating PCB is its bonding capability.

Due to presence of other elements, hard gold soldering is more difficult compared to ENIG plating.

Thermostatic bonding, ultrasonic wire bonding or other delicate joining are exceptionally difficult with PCB hard gold plating.

  • ENIG Plating

ENIG PCB surface finish is softer compared to hard gold plating, with grain sizes roughly 60 times bigger. ENIG plating hardness ranges from 20 to 100 HK25, and can withstand just 35g or less of contact force.

Typically, ENIG plating lasts for lesser cycles in comparison to PCB hard gold plating. ENIG plating purity makes it more corrosion-resistant compared to hard gold plating, although it might be susceptible to scratch considering its softness.

Moreover, thermostatic joining, ultrasonic wire joining or other sensitive bonding techniques are easier with ENIG plating PCB.

ENIG Plating PCB

ENIG Plating PCB

Which Are The Available Hard Gold Plating Solutions?

Due to its cost, it is often crucial to deposit gold just in those sections and at thickness necessary for the PCB application. Hence, there are a number of selective methods for PCB hard gold plating that continue to be advanced including:

  1. Cyanide-Based Gold-Plating Solution

Majority of gold plating is performed using solutions consisting of gold in the form of soluble cyanide composite. The reaction between gold and alkali cyanide forms either trivalent alkali gold cyanides or monovalent alkali gold cyanides.

  1. Alkaline Color-Flash Golds

Formulation of color-flash golds makes it produce thin films of defined color. This PCB hard gold plating solution generally comprise of fairly small quantities of gold (0.5-1.5 g/L).

Typically, color-flash gold solution does not contain brighteners. Also, the gold plating solution is not abrasion-resistant because the deposits are greatly alloyed and extremely narrow (0.025–0.075 μm).

  1. Neutral Golds

Neutral golds constitute very broad range of electrolytes for applying exceptionally pure, soft gold deposits for hard gold plating PCB applications. It lacks free cyanide and the electrolytes are formulated on phosphonates, phosphates, or salts of several organic acids.

Hard gold plating PCB from neutral golds normally have excellent wirebonding ability and solderability. These features are related to high purity and softness.

  1. Acid Hard Golds

Acid hard gold solutions contain 99.7 percent or higher of gold and you can maintain both physical properties and composition. It is the preferred hard gold plating solution for separable PCB connectors.

This electroplating solution is suitable for PCB gold plating procedure at extremely elevated current densities. It also ensures uniform distribution of deposit and is compatible with several kinds of selective plating mechanism.

Most present electrolytes are formulated from weak organic acids and their resultant salts.

Based on the electrolyte selection, you can add metallic brighteners in chelated, complexed or simple form. Also, you can incorporate depolarizing agents, range extenders and surfactants if necessary.

  1. Noncyanide Gold Plating

Gold can be deposited from the chloroaurate. Various other forms, such as the iodide,
thiosulfate, thiocyanate and thiomalate also have been proposed, but have not been commercialized.

  1. Monovalent Gold Strikes

Here, you enhance the nucleation of crystallite to grain growth ratio by working at greater-than-usual current densities. Strike solution consists of only a small quantity of metal.

  1. Trivalent Golds

In this hard gold plating solution, chloroauric acid reacts with alkali cyanide to yield alkali gold (III) cyanide. Typically, cyanide-containing solutions produce finer-grainer grained gold deposits.

What Is The Use Of Gold Fingers In PCB?

The purpose of gold fingers is to link contacts between 2 adjoining printed circuit boards. Besides its conductivity, the gold helps in protecting the linking borders from wear due to regular use.

 PCB Gold Finger

PCB Gold Finger

Gold fingers enable you to connect, disconnect and reconnect PCB as much as a thousand different times within a matching slot. This is because of hard gold strength at its designated thickness.

The functions of PCB gold fingers are versatile. Some of the common applications of gold fingers consist of the following:

  • Interconnection Points

If a secondary circuit board links to the primary PCB, it is connected via one of the many female slots, like AGP slot. The gold fingers transmit signals between peripheral devices via these slots

  • Special Adapters

Gold fingers allow you to incorporate several performance enhancements onto the hard gold plating PCB.

  • External Connections

The external peripherals added connect to the primary circuit board through the PCB gold finger.

Gold fingers give hard gold plating PCB the ability to function and deliver modern functionality in various circuit board uses.

Why Must You Plate PCB Fingers With Gold?

Generally, PCB contact points are subjected to constant insertion and removal due to their interconnection purpose. Therefore, the fingers will rapidly wear out and impede the hard gold plating circuit board performance.

The process of plating the contact parts using gold boosts their longevity. Gold is the best options due to its outstanding electrical conductivity after silver and copper and exceptional corrosion resistance.

Moreover, it is possible to alloy gold with nickel or cobalt to boost its wear and tear resistance.

The inert nature of gold makes it the right choice for fabricating contact parts more subjected to wear and likely to oxidize. Though at times you can use silver, it is not perfect for commercial PCB applications since it readily reacts with chlorides and sulfides.

How Does Immersion Gold Plating Compare To Hard Gold Plating PCB?

There exist several differences between hard gold plating PCB and immersion gold plating PCB including:

  1. Immersion gold PCB has greater gold thickness in comparison to hard gold plating circuit board. Additionally, immersion gold circuit boards are more yellow compared to hard gold plating types, since the latter includes color of nickel.
  2. Different crystal structures. Immersion gold PCB has a denser crystal structure than hard gold plating boards, hence it is difficult to form oxidation.
  3. It is easier to solder immersion gold PCB with minimal poor solder problems. Moreover, you can effortlessly control stress in immersion gold boards, which is an advantageous feature for bonding purposes.
  4. Immersion gold plating board exhibits poor anti-abrasion property with respect to gold fingers. This is because immersion gold is highly flexible compared to hard gold plating PCB.
  5. You use nickel only on the pad of immersion gold plating PCB. Therefore, the transmission of signal within the skin effect has no impact on the copper layer signal.
  6. With the stringent requirements for greater precision during PCB manufacturing, trace spacing and width should be below 0.1mm. It is easier to form short circuit in hard gold plating PCB in comparison to immersion gold plating circuit board.
  7. Since you only use nickel on the immersion gold PCB pad, the solder bonds firmly with copper layer.
  8. Immersion gold PCB is smoother and has longer service life than hard gold plating board.

 Immersion Gold PCB

Immersion Gold PCB

Which Are The Design Rules For Hard Gold Plating PCB?

Some of the design rules necessary for edge connectors or gold fingers of hard gold plating PCB include:

  • No plated thru-holes are permitted within the plated region.
  • There should be no silkscreening or solder mask within the plated section.
  • With hard gold plating PCB panelization, often position the gold fingers overlooking outward from the center of PCB panel.
  • Link all gold fingers using a 0.008 inch conductor track at the boundary to facilitate fabrication.
  • You can place hard gold plating PCB components on a single or both surfaces to a 25mm depth from the exterior edge.

What Is The Recommended Thickness Of PCB Hard Gold Plating?

You can vary the thickness of hard gold plating PCB through controlling the gold plating cycle duration. Though the usual minimum gold fingers values are:

  • IPC Class 1 and 2: 30u” over 100u” nickel
  • IPC Class 3: 50u” over 100u” nickel

Generally, hard gold plating is not put on solderable areas due to its comparatively poor solderability and high cost.

IPC considers 17.8u” as the maximal thickness that is solderable. Therefore, when using PCB hard gold plating, the preferred nominal thickness ought to be approximately 5-10u”.

How Do You Perform PCB Hard Gold Plating?

The process of PCB hard gold plating starts after copper etching of the PCB laminate to leave just the required regions bare. You then electroplate an underlayer of nickel onto the bare PCB with 50 micro-inch minimum thickness.

Apart from providing mechanical support, nickel also gives a diffusion barrier coupled with acting as inhibitor to creep and pore corrosion. Consequently, immersed inside a salt medium, you then electroplate the hard gold directly onto the surface of the nickel underplating.

Quality control for PCB hard gold surface finish includes tape adhesion and thickness tests. As you know, gold price needs strict process controls since the cost for mistakes are significant.

What Is The Difference Between PCB Hard Gold Plating And Soft Gold Plating?

Soft gold plating and hard gold plating are the key types of PCB gold plating processes. Although there is duplex gold plating which a blend of the two techniques.

Let’s briefly discuss these 3 major methods of PCB gold plating:

  • Hard Gold Plating

With hard gold plating, you add a small quantity of an alloying compound or element. This is instrumental in enhancing the wear and hardness features of gold deposit.

Nickel or cobalt are the common elements added, but you can use arsenic or iron as well.

Hard gold deposits exhibit a polished grain structure that gives a more brilliant general gold appearance. Because of the enhanced hardness, hard gold plating PCB is suitable for applications involving recurrent interaction or sliding contact.

 Soft Gold Vs. Hard Gold PCB Plating

 Soft Gold Vs. Hard Gold PCB Plating

  • Soft Gold Plating

Different from hard gold plating PCB, soft gold plating basically contains pure gold having 99.9 percent or more purities. Soft gold has a grain structure that is less refined compared to hard gold, making the gold deposit possess a 90 knoop maximum hardness.

Soft gold plating is ideal for high temperature PCB applications or wire bonding because its high purity develops no compounds or oxides. It is perfect for low-load, static connector designs like lapping connections.

Often, soft gold plating is recommended for medical PCB applications because of the biocompatibility and high purity of the finish.

  • Duplex Gold Plating

Here, you apply both soft and hard gold to form a PCB surface finish having features of both types of gold plating.

For instance, you can top coat a greatly corrosion-resistant soft gold layer with hard gold deposit.

This is instrumental in improving the wear characteristics of the general PCB gold plating finish.

Duplex gold plating PCB finish equally features reduced general deposit porosity because of the contrasting grain structures of the 2 gold layers.

This may offer improved corrosion resistance at reduced general gold consumption in comparison to single layer gold plating.

What Are The Factors To Consider When Performing PCB Hard Gold Plating?

Here are the key considerations during hard gold plating PCB manufacturing process:

  1. Nickel Underlayer

Nickel plating ensures a blocking impact on the diffusion or migration between copper and gold. This the main factor to consider during PCB hard gold plating.

Via positive oxide surface, the nickel offers an efficient barrier that obstructs the pores and substrate.

This gives a hard layer below the gold plating surface finish and minimizes possibility of pinhole corrosion. Moreover, the support layer prolongs the lifespan of the hard gold plating PCB.

  1. Porosity

During electroplating operation, gold nucleates on several stains exposed on the PCB surface to develop a permeable electroplated circuit board surface.

There is some relationship between the hard gold plating porosity and coating thickness.

The porosity speedily increases below 0.38 μm and is very low above 0.76 μm.

There is also relationship between porosity and substrate flaws like improper stamping, stamping marks, laminates, inclusions among others.

  • Wear

The wear or lifespan of the gold plating PCB relies on two properties of the board surface treatment: hardness and friction coefficient.

Reducing the friction coefficient increases the life of hard gold plating PCB surface finish. Hard gold plating enhances the gold deposits’ wear resistance.

What Are The Disadvantages Of Hard Gold Plating PCB?

The primary drawbacks of hard gold plating PCB include:

  • Extra high cost
  • Additional complex fabrication processes.
  • Etching undercut may result in flaking/slivering
  • Finish doesn’t entirely enclose sidewalls of trace, save for gold finger sections.

 Which Are The Two Crucial Quality Control Tests For Hard Gold Plating PCB?

The two important quality analysis tests for PCB hard gold plating include:

  • Thickness Test

X-Ray Fluorescence Spectroscopy enables you to accurately measure the thickness of hard gold plating non-destructively.

It allows you to measure the gold plating thickness on fine-pitch and large PCB components.

 Thickness Testing of Hard Gold Plating PCB

Thickness Testing of Hard Gold Plating PCB

  • Tape Test

This test examines the hard gold plating adhesiveness on the PCB. Here, you run a tape strip along the hard gold plating PCB.

Remove the tape and examine it for evidence of gold plating. The plating has insufficient adhesion in case there are any traces of gold plating on the tape.

Why Is A Nickel Underplate Necessary During PCB Hard Gold Plating?

You should consider the right choice of an underplate to improve hard gold plating PCB wear resistance.

Popular underplate comprise of bright electrolytic nickel, high purity sulfamate nickel or electroless nickel.

Applying nickel underlayer before PCB hard gold plating plays many roles including:

  • Diffusion Barrier

Nickel underplate before PCB hard gold plating gives a barrier to metallic diffusion between alloying metals and copper base metals.

The diffusion barrier makes sure that poorly bonded intermetallic layers don’t develop between the gold and base metal.

As a result, this protects the integrity of hard gold plating PCB with time. This is particularly vital for applications of hard gold plating PCB involving high temperatures.

  • Corrosion Inhibitor

The nickel underlayer is also essential in promoting corrosion resistance.

Any pores within the gold coating will advance into the nickel underplating instead of the hard gold plating PCB substrate.

This typically leads to passive formation of oxide at the base of the pore. This happens so long as the surrounding does not have high content of acidic corrosives.

The nickel underlayer hinders the growth of tarnish films or copper oxide to the hard gold plating surface.

Consequently, it protects the oxide-free PCB contact surface.

  • Leveling Layer

Brightened nickel underlayer can help in enhancing the contact surface’s finish. This in turn minimizes the friction coefficient thus decreasing the sliding wear of hard gold deposit.

  • Load Bearing Underlayer

Nickel underplate is vital in holding the contact load of hard gold plated PCB component.

This minimizes the cracking possibility of gold-plated contacts and improve the general hard gold plating PCB wear resistance.

What Are The IPC Standards For Hard Gold Plating PCB?

The IPC standards for PCB hard gold plating include the following:

  • Chemical Composition: To ensure maximum rigidity across the PCB contacts edges, the hard gold plating needs to constitute between 5-10 percent cobalt.
  • Thickness: The gold fingers’ plating thickness needs to be often within the 2 – 50 microinches range. By size, the standard thicknesses are 0.125 inches, 0.093 inches, 0.062 inches, and 0.031 inches.

The smaller thicknesses are typically applied for hard gold plating PCB prototypes.

On the other hand, the greater thicknesses are utilized across connecting edges which are often lodged, dislodged and relodged.

  • Visual test: Hard gold plating PCB Gold fingers need to pass an optical test performed using a magnifying lens.

Ensure that the edges have a polished, clean surface that is free of appearance of nickel or excessive gold plating.

At Venture Electronics, we offer a range of hard gold plating PCB depending on your unique requirements and specifications.

Contact us today for all your hard gold plating PCBs.

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