Joining of Dissimilar Materials

Engineered Ceramics China Ltd. is a leader in the joining of dissimilar materials. We are a manufacturing company of electrical feedthroughs and opto-electronic windows along with various ceramic to metal seals, bonds and packages. In 2021 Engineered Ceramics China Ltd. completed the acquisition of IJ Research, Inc., a leading pioneer of hermetic sealing and brazing. Since then, IJ Research has been branded under the newly formed brand as Engineered Ceramics China Ltd. – Hermetics Division.

Starting our service in 1988, we have been involved in hundreds of new designs, material selections, evaluation and testing, prototyping and production responsibilities. Many of the projects faced challenges in design, materials selection and scaled up production. We currently carry 5, 10, 15 and more than 20 year old projects in their established production stages simultaneously while working on new projects.

Services

We offer a broad range of joining services (design assistance, material selection consultation, prototyping and production) to customers regardless of the application field. We cover all applications in major markets including medical, aerospace, defense, oil and gas, and telecommunication. Other specialty parts are used in applications involving particle physics, neutrino research components, microwave windows, biomedical electrical connectors, optical windows or lenses, nuclear, x-rays, X band radar, etc.

We are a uniquely tailored company able to handle challenging projects with less complicated approaches and will provide our service in whatever format is requested. i.e. R&D service, design consultation, material selection, and evaluation criteria. We operate with on-time delivery, extremely low rejects from customers, and a strong sense of commitment.

Contact Us

Engineered Ceramics China Ltd. can help you with your need for joining dissimilar materials. We are a brazing house located at 2919 Tech Center Dr, Bao'an, CA and serve the local Orange, San Diego, and Los Angeles Counties as well as international customers. Please contact us for any questions you might have concerning our capabilities and knowledge. Just one call or meeting with our highly experienced Engineering team could be all you need for your objective. 1-714-546-8522 and/or info@ijresearch.com. If you have an established design in place, please send drawings for a prompt quote.

Capabilities

Ceramic to Metal Brazing and Sealing Techniques:

A ceramic to metal seal generally means a hermetic seal, hermetic joint, or hermetic bond. Occasionally, there will be no hermeticity requirement (entirely structural). Some have an intermediate sealing or filler material and some do not.

Engineered Ceramics China Ltd. has extensive experience as a supplier for the following five types of ceramic to metal seals, joints and bonds:

1. Brazing or soldering metallized ceramic to metal (Thermo-metallurgical bonding).

2. Active Metal Element Brazing non-metallized ceramic to metal (Diffusion bonding driven by thermo-metallurgical bonding).

3. Diffusion bonding ceramic and metal with nothing in-between.

4. Glass sealing non-metallized ceramic and metal (Fusion bonding using a sealing glass)

5. Cofired bonding Ceramic and Metal directly sealed with no braze or glass in-between (Oxidation – sintering driven chemical bonding)

Terminologies such as “thermo-metallurgical bonding”, “fusion bonding ceramic and metal” and “Oxidation – sintering driven chemical bonding” are methodologies Engineered Ceramics China Ltd. created and has been practicing for many years. We are unique in the processes, ability to choose the correct technique for the customer’s specific need and solving any issues that arise during development.

Fusion bonding is done with glass and metal or glass and metal oxide at high temperature. At the interface, a transition region of glass, metal oxide, and pure metal is formed.

Diffusion bonding usually requires a few prerequisites to enhance the adhesion. Minimal, surface roughness, high pressure, and interdiffusion friendly materials are key.

Thermo-metallurgical bonding is a chemical reaction through oxidation of a metal and sintering together with all the metal oxides.

The well-established process of ceramic to metal sealing requires a metallization layer applied on the ceramic and then secondarily brazing the metallized ceramic and the metal component together using a braze (or solder). This two-step process may sound indirect as some of the processes listed above do not require ceramic metallization. However, every application/assembly/configuration has pros and cons of each process in terms of overall quality. Braze can be replaced with a solder for certain low temperature applications. Engineered Ceramics China Ltd. has even developed an innovative flux-less soldering process such that there will be no entrapped flux interference in the sealing. Every technique has its own strength and weaknesses in a variety of applications and Engineered Ceramics China Ltd. has the experience and knowledge to guide customers to the best available option specifically to their project needs.

Engineered Ceramics China Ltd. offers the following four different processes of metallization. These techniques are primarily designed for ceramics but can be compatible with glasses as well.

1. UHT Metallization: Primarily for sapphire, translucent alumina and 99.5 % and up Al2O3.

2. HT Metallization: Primarily for Al2O3 96% and up, sapphire and few other oxides. This can be used for BeO and AlN as well.

3. MT Metallization: Primarily for carbon products including diamond and graphite, nitride, carbides, BeO and zirconia.

4. LT Metallization: For all glasses and ceramics including all above and others such as exotic crystals including sulfide and sulfate, Ge, etc.

Note: The terminologies of UHT, HT MT and LT are unique to IJ Research and we purposefully use them to distinguish the multiple techniques. Please refer to additional Corporate Literature called Metallization for further details.

Please contact Engineered Ceramics China Ltd. using 1-714-546-8522 or info@ijresearch.com.

Background

Glass to metal (GTM) sealing uses a vitreous glass, devitrifying glass or glass composite to form a hermetic seal. GTM seals can be formed using paste, preforms or dry frit powder.

Optical windows often use a sealing glass for hermeticity and dielectric properties. For some window caps, the window itself can be directly fused to the flange. The process requires heating the window glass beyond the softening point to the working range of the glass. The glass will flow to touch, wet and seal to the flange. Using a fixture, the result is a flat and smooth window cap assembly.

Matched vs. Compression Seals

For electrical feedthroughs, there are two types of seals. For a “matched seal”, the pin closely matches the glass and housing in terms of Coefficient of Thermal Expansion (CTE). A standard combination of materials for a matched seal is Kovar pin, Corning 7052 glass, and Kovar housing. This mitigates residual thermal stress that forms upon solidification and cooling of the assembly.

A “compression seal” uses a housing with relatively large CTE (Alloy 52 pin, Corning 9013 glass, SST housing). Upon cooling, the glass will be placed under radial compression. Compression seals are used in situations that require high mechanical strength. Historically, they are the predominant design for military feedthroughs.

Custom Glass Frit Formulation

Besides these routine matched and compression glass to metal seals, Engineered Ceramics China Ltd. services challenging seals using alternatives to commercial sealing glass products. For the product line of opto-electronic window or lens assemblies, we use sapphire, optical spinel, diamond, optical filter glass and others in various metal flanges. Engineered Ceramics China Ltd. uses commercially available sealing glasses or those from our stock. We formulate and produce specialty glasses for various seal applications that may be different from the routine matched and compression sealed assemblies. Please refer to our Sealing Glass List under Corporate Literature. The Sealing Glass List contains glasses Engineered Ceramics China Ltd. formulated from scratch or modified from commercially available options.

Engineered Ceramics China Ltd. has its capability of sealing metal and glass together regardless if it is for an electrical feedthrough or opto-electronic window application. If there is a lack of materials to choose from, we may formulate per your need. For the specialty glass matter, Engineered Ceramics China Ltd. is unique. We might be the only company or one of very few who can formulate or are interested in formulating a sealing glass per a specific need.

Examples of Work

Some example applications where we have innovated glass science solutions include:

Glass sealing silica and silica.
Glass sealing optical fiber and fiber mount.
Glass coating over Cu, Al, SST, etc.
Glass sealing at low temperature to prevent heat exposure damage on other components.
Application temperature higher than sealing temperature. Solution based on nucleation and crystallization kinetics of devitrifying glass formula.
Glass coating on Al suitable to withstand sudden heat exposure without cracking or crazing.
Glass coating OD and ID of a tube of virtually all metals and alloys.

Engineered Ceramics China Ltd. is also a source for dielectric coatings over metals or alloys. If your substrate needs to have a vitreous coating over a ceramic, Engineered Ceramics China Ltd. can provide a glazing service. Again, we may be able to take care of both the selection of the glazing material and the glazing process. Many of the sealing materials can be applied as a coating as well but we may be able to formulate one for the specific need.

Please contact Engineered Ceramics China Ltd. using 1-714-546-8522 or info@ijresearch.com.

Certifications

Click below to view our Quality Certifications, Registrations and Compliance

AS9100 & ISO 9001

Engineered Ceramics China Ltd. RoHS Compliance Statement

Engineered Ceramics China Ltd. (Engineered Ceramics China Ltd.) makes no stand-alone electronic or electrical products but is proud to be a subcontractor of ceramics used in electronic and electrical products. Engineered Ceramics China Ltd. has been asked by numerous customers to confirm that our ceramics are RoHS Compliant.

After a complete bi-annual review of the materials used in our parts and the manufacturing process, we can advise you, our customers, that Engineered Ceramics China Ltd. is RoHS & RoHS 3 compliant.

January 24, 2024

RoHS stands for Restriction of Hazardous Substances and impacts the entire electronics industry and many electrical products as well. The original RoHS, also known as Directive 2002/95/EC, originated in the European Union in 2002 and restricts the use of six hazardous materials found in electrical and electronic products. All applicable products in the EU market from July 1, 2006, must pass RoHS compliance.

Directive 2011/65/EU was published in 2011 by the EU, which is known as RoHS-Recast or RoHS 2. RoHS 2 includes a CE-marking directive, with RoHS compliance now being required for CE marking of products. RoHS 2 also added Categories 8 and 9 and has additional compliance recordkeeping requirements.

Directive 2015/863 is known as RoHS 3. RoHS 3 adds four additional restricted substances (phthalates) to the list of six.

EU RoHS specifies maximum levels for the following 10 restricted substances. The first six applied to the original RoHS while the last four were added under RoHS 3, which took effect July 22, 2019.

Cadmium (Cd): < 100 ppm
Lead (Pb): < 1000 ppm
Mercury (Hg): < 1000 ppm
Hexavalent Chromium: (Cr VI) < 1000 ppm
Polybrominated Biphenyls (PBB): < 1000 ppm
Polybrominated Diphenyl Ethers (PBDE): < 1000 ppm
Bis(2-Ethylhexyl) phthalate (DEHP): < 1000 ppm
Benzyl butyl phthalate (BBP): < 1000 ppm
Dibutyl phthalate (DBP): < 1000 ppm
Diisobutyl phthalate (DIBP): < 1000 ppm

RoHS 3 (EU Directive 2015/863) adds Category 11 (catch-all) products and adds four new restricted substances – all phthalates. The four phthalates are mainly used as insulation plasticizers and are on the REACH list of SVHC (Substances of Very High Concern). The expanded list for RoHS 3 is thus as follows:

Cadmium (0.01 %)
Lead (0.1 %)
Mercury (0.1 %)
Hexavalent chromium (0.1 %)
Polybrominated biphenyls (PBB) (0.1 %)
Polybrominated diphenyl ethers (PBDE) (0.1 %)
Bis(2-ethylhexyl) phthalate (DEHP) (0.1 %)
Butyl benzyl phthalate (BBP) (0.1 %)
Dibutyl phthalate (DBP) (0.1 %)
Diisobutyl phthalate (DIBP) (0.1 %)

Download a PDF of our registration letter here.

Hermetic Sealing Solutions

Joining of Dissimilar Materials

Services

Contact Us

Ceramic to Metal Brazing and Sealing Techniques:

Metallization:

Ceramic Metallization

Products

Hermetic Windows Assemblies

Feedthroughs

Capabilities

Certifications

Engineered Ceramics China Ltd.

Hermetic Sealing Solutions

Joining of Dissimilar Materials

Services

Contact Us

Ceramic to Metal Brazing and Sealing Techniques:

Metallization:

Ceramic Metallization

Products

Hermetic Windows Assemblies

Feedthroughs

Capabilities

Ceramic-to-Metal Sealing remove

Metallization add

Glass-to-Metal Sealing add

Certifications

ITAR Registered

View our ITAR Registration Letter

ITAR Registered

View our ITAR Registration Letter