Kovar

A reliable source for Nickel information and leading Nickel Companies & Suppliers.

Kovar was specifically formulated as a sealing alloy for glass and ceramic materials (specifically for compatibility with the thermal expansion characteristics of borosilicate glass). Read More…

Kovar Also known as Rodar, Kovar is a registered trademark that refers to a low expansion alloy that is composed of iron, nickel, cobalt and trace amounts of the elements manganese, silicone and carbon.

Leading Manufacturers

Long Island City, NY  |  800-767-9494

We supply Nickel and its alloys for a broad range of applications. metalmen provides supply solutions – we respond with quick quotes and on-time deliveries.

Request A Quote

Metalmen Sales Inc. $$$

Pompton Plains, NJ  |  800-838-1978

Our company may have started small, but we quickly grew to handle the largest aluminum orders. Our metals are made from the highest quality materials, and we pledge to offer superior service to all our customers.

Request A Quote

Metal Associates $$$

South Norwalk, CT  |  203-838-5700

Since 1986 Magellan has been serving the global aerospace, oil & gas, power generation, petrochemical, bio-medical, pharmaceutical and other high tech manufacturing industries. Suppliers of nickel alloys, titanium, stainless steel and duplex alloys throughout the United States and in over 45 countries.

Request A Quote

Magellan Metals $$$

Solon, OH  |  888-539-5602

Versatile is a good way to describe us. We are a service center that processes aluminum, stainless steel, copper, brass, phosphor bronze, nickel silver, Hastelloy, Inconel, Monel and other metals, specializing in supplying a variety of foil and sheet gauged stock items. You are not held to a minimum order. We will process metal sheets in widths up to 48", lengths of up to 144".

Request A Quote

Comet Metals, Inc. $$$

Cleveland, OH  |  440-250-1900

For over 30 years, we have provided metal forged products for a wide variety of industries, including the aerospace, military, food service, medical, and automotive industries. Our customers know they can trust our forgings for quality and affordability. We will never try to make you pay more than you should for our products. Contact us by phone or email to find out more!

Request A Quote

Ferralloy Inc. $$$
placeholder image Metalmen Sales Inc. Metal Associates Magellan Metals Comet Metals, Inc. Ferralloy Inc.

The material is used by many industries, including electronics, medical, semiconductor and industrial manufacturing, to provide exceptional hermetic seals for applications such as power tubes, vacuum tubes, transistors, microwave tubes, diodes, integrated circuits, and x-ray tubes.

Most often used in applications requiring a glass to metal seal, Kovar is vacuum melted, meaning that it has undergone melting, refining, and casting under a vacuum. An additional property of Kovar is that at any temperature under that of the Curie point (435°C or 815ºF) it is magnetic. Kovar is very similar to another nickel alloy referred to as Invar.

Invar is a nickel steel alloy with specific thermal expansion properties; however, Invar is unique for its low thermal expansion qualities, while Kovar is for its low thermal expansion in terms of its compatibility to heat-resistant glass.

Kovar is specifically composed of 54% iron, 29% nickel, 17% cobalt, .2% silicon, .3% manganese and less than .01% carbon. This chemical composition has narrow limits that are very controlled in order to ensure optimal thermal expansion compatibility. Kovar can be fabricated into shapes and parts such as sheets, rods, plates, bars and tubing through a variety of heat treating processes including annealing and forging.

Although high temperatures are not critical when annealing Kovar, temperatures greater than 900°C (1652ºF) are not recommended because the high heat will promote grain growth. When it comes to forging Kovar, the biggest concern is that the Kovar must be heated quickly in order to avoid soaking within the furnace which can affect the surface appearance of the alloy.

In addition to manufacturing processes, there are many types of secondary services that are commonly used on Kovar including turning, drilling, tapping and reaming. When it comes to turning Kovar, it is necessary to pay attention to the angle of the cutting tools.

For drilling Kovar, it is the speed of the drill and the resulting feed that must be taken into consideration, and it is the same for reaming, but with different required proportions. Lastly, when it comes to tapping Kovar, the speed should be around 20 feet per minute (FPM) and it is recommended to use either nitrided or electrolyzed tools.

Kovar Informational Video