Kovar is a nickel–cobalt ferrous alloy that is designed to have substantially the same thermal expansion characteristics as borosilicate glass. The expansion characteristics of Kovar match both borosilicate (or Pyrex) glasses and alumina ceramics, making it one of the most popular of the controlled expansion alloys for hermetic sealing applications. Kovar is porosity free and is produced to ensure good properties for machining and deep drawing.
Kovar Substrate Plating with Gold
The electrodeposition on Kovar process can be extremely complicated if done incorrectly. There are several steps that must be completed with absolute precision for the plating on Kovar process to be effective. Due to its excellent electrical conductivity and ease of use gold is often utilized in Kovar substrate plating. Gold plated Kovar is often used in high reliability applications where a heat treating step is employed. The following steps are considered a general guideline for the Kovar plating process:
- Soak clean
- Cyanide activate
- Gold strike
- Gold plate
Gold is one of the most non-reactive of all metals. It is unaffected by moisture and heat, and will not oxidize, which means that gold will not rust, and the overall wear will be kept to a minimum. Gold also conveys good electrical conductivity, which is a proven commodity for the electronics field
Although gold’s electrical conductivity might fall short to some other metals, it has been proven time and time again to be well suited for the electronics field. Because corrosion cannot occur, gold cannot build a coating of poor conducting or effect the transmission of electrical current and is able to withstand electrical connections that create elevated temperatures.
Kovar Nickel Plating
When gold is applied to a Kovar substrate, metal ions within the alloys of the Kovar will diffuse into the gold layer and degrade its hardness and non-oxidizing properties. An anti-diffusion underplate such as nickel (electroless or sulfamate) should be applied to prevent this.
In addition, it is recommended that a Kovar nickel plating finish be used under the gold plating where part flexure or deformation is not expected, and a bright finish is desirable. Where part flexure or deformation is expected, it is recommended that sulfamate nickel as the underplate be used since it has a higher ductility.
Established Applicable Benefits of Electrodeposition on Kovar
Kovar is a low expansion iron alloy that is most commonly used in electronics applications. Kovar has a high nickel and cobalt content and is traditionally an alloy that was used for metal-to-glass sealing because of its low coefficient of thermal expansion. It also provides a hermetic seal that is used to protect devices in many different industries. These advantages combined with the benefits of Kovar gold plating or Kovar nickel plating create a specialized material with many unique properties.
Kovar Substrate Finishing Applications
Kovar plating is often used in applications requiring a hermetic seal between the metal alloy and the glass or ceramic component. The hermetic seal creates a bond free of the trouble and failures caused by dirt, dust, moisture, fungus or lack of pressure at high altitudes. As a result, Kovar provides many advantages in demanding end-use applications that operate in strict environments, including military, aerospace, medical, commercial and aviation industries. Some of the other plating on Kovar applications, include:
- Microwave tubes
- Hermetic seals
- Power tubes
- X-ray tubes
Kovar Plating Specifications
Our electrodeposition on Kovar services meet various Mil-Spec standards. The constant monitoring and frequent testing of our chemistries helps us maintain optimum quality. Some of the other applicable specifications for plating on Kovar, include:
Analytical Lab for Kovar Plating
ENS Technology is the only metal plating company in Northern California to maintain a fully equipped, on-site analytical laboratory. Our fully PhD-credentialed chief chemist oversees all lab operations, including plating bath chemistries, wastewater protocols, and the technical monitoring of our dedicated R&D plating line.
Quality Control Services for Kovar Substrate Plating
Our electroless nickel plating quality control custom services for electrodeposition on Kovar are handled by our highly trained technical specialists and production staff that provide expertise, leadership and high standards of excellence. ENS is committed to implementing business improvement processes. Our custom service electroless nickel plating quality control process provides the keys to continued improvement and overall customer satisfaction.
Contact ENS for Kovar Substrate Plating Today