Category Archives: Portfolio

Background

Industry – Medical device

Requirement

An anti-reflective (AR) coating needed to be applied over a sapphire window and survive 1,000C high temperature braze processing. The coating of the sapphire could not show any physical delamination, crazing, or degradation of the optical properties such as transmission and/or reflectance in the specific spectral regions.

Materials Used

Titanium alloy – FDA approved
Optical window –Sapphire with AR coating

Challenges:

Sapphire is an excellent optical material for the visible range of the spectrum with a transmission of approximately 85%. The project required even greater transmission via application of an A/R coating.  Hermeticity requirements along with the 5,000 cycle autoclave ability meant no low temperature solder could be considered. Therefore, the whole assembly needed to be bonded by brazing. Typical, A/R coatings such as MgF2 and CaF2 cannot withstand these conditions.

The primary issue was how to ensure the selected A/R coating adheres to the sapphire without delamination, crazing or any changes of optical properties.

Solution:

Over the course of a few months IJ Research developed its own custom AR coating that withstands braze processing, shows minimal and predictable spectrum shift, and negligible degradation of transmission performance before and after brazing.

Results:

The resultant brazed assemblies with the new anti-reflective coating established an immediate market advantage for our customer. Our unique coating expertise was able to enhance the performance of their units well beyond that of any competition. This project demonstrated the diverse utility of IJ Research’s in-depth material science background to all projects and clients.

Background:

Industry – Aerospace
Materials Used – Oxygen Free Copper (OFC), Borosilicate Glass (Corning 7740) and Silicon semiconductor.

Requirement:

To maintain a robust hermetic seal under extreme thermal gradients. Liquid hydrogen needed to be stored in a glass tube section sealed on opposite ends to two extremely divergent materials with polar opposite material behaviors (Silicon and OFC).

Challenges:

How to hermetically bond and maintain a durable connection between a low thermally conductive material (silicon) on one end, and a highly thermally conductive metal (OFC) on the other.

Solution:

IJ Research performed an exhaustive evaluation of the appropriate approach to a robust hermetic seal. Once completed, a multitude of innovative steps were taken to resolve the base difference is thermal and mechanical behaviors such that the parts succeeded in testing. Once IJ Research had fully validated the hermetic seals of the assembly it was then exposed to a tremendous thermal shock of -299°C and then immediately to +400°C, while still maintaining full hermeticity.

Background

Industry – Medical device

Requirement

To seal an oxide ceramic and Titanium alloy with nothing in-between. The most common sealing material in medical implant is pure Au. In this situation, however, the FDA approval was based on the direct seal of the ceramic and metal with no Au braze in-between.

Materials Used

Titanium Alloy – FDA Approved (Not specified intentionally)
Ceramic – Biocompatible Stabilized Zirconia

Challenges:

The customer had limited time to get a new implantable medical device to market. Having to approve an additional material at the expense of trial and evaluation costs would have doomed the project such that bonding via brazing was not possible. Faced with time constraints and a non-typical material combination, a disciplined, efficient and innovative approach was required.

Solution:

After a deep level review of the viable options to process these components in the allotted time, IJ Research recommended the best option possible. The decision was to develop a diffusion bonding process in as short as time as permissible which would end up being just a few weeks. Using IJ Research’s material science background to its advantage, the joint was designed to promote the movement of Titanium atoms into interstitial sites of the ceramic lattice structure providing an interdiffusion bonding interface of angstrom thickness. All the required conditions of the component parts for such processing were also completed in the limited timeframe.

Results:

The optimization of the process parameter was successfully completed in the limited timeframe. The customer was able to integrate the design into the product with no need of additional material evaluation, clinical studies, and more importantly no need of any additional FDA approval.

Years later, IJ Research developed a direct bonding process of green body ceramic and metal for hermetic seal applications. Please refer to the Technology section of this website for more information.

Background

Industry – Aerospace

Materials Used

IJ Research specified high temperature metal
IJ Research specified high temperature ceramic
IJ Research specified metallization system and braze

Requirement

To seal two metal ring washers with a ceramic disc sandwiched for a thermal cycle application between room temperature and 850 °C while hermeticity is maintained throughout the extreme thermal excursions. For the oxidizing environmental condition of the application, the braze material needed to be non or slowly oxidizable without thermal degradation in the seal area.

Challenges:

There are myriad issues for applications with multiple requirements like this. Mainly, what materials should be used to meet the entire requirement and how to process so that the sealing itself is not damaged in service.

Solution:

Understanding thermo-mechanical behavior of the materials in application requirements permitted IJ Research to quickly introduce the optimal materials for the project.

Results:

The utilization of the low grain boundary ceramic oxide material proved extremely robust in application and provided even better performance than our customer had anticipated.

Background

Industry -Aerospace/Optoelectronics

Materials Used
Quartz window (with AR coating)
SST 304L housing

Requirement

To Indium solder and hermetically seal quartz glass window in SST housing with no flux for an ultrahigh vacuum application.

Problem:

Most solders oxidize in atmosphere and increase their surface tension making solder flow and fill behaviors more difficult and ultimately making a strong, hermetic seal challenging. Flux very effectively reduces the surface tension of the solder so that it can flow into the areas desired for bonding and increasing the overall likelihood of a successful bond. However, geometry that does not allow the flux to evaporate during processing can lead to flux entrapment that can severely impact hermetic performance. Due to the extreme coefficient of thermal expansion (CTE) mismatch between quartz (50×10^-7/C) and SST 304 (170×10^-7/C), high temperature brazing was not an option.

Solution:

Our solution was to develop a custom process that lowered the surface energy of molten solder without using flux. Our technique provides extremely low surface energy solder and increases the flow characteristics of the molten solution. Many customers come into processing with the understanding that flux will enhance their hermetic sealing area. What they have not seen is the issues caused by flux entrapment that can severely compromise hermetically sealed joint areas. IJ Research has developed a unique processing method were solder material can be brought to its liquidus and hermetically seal with no need for flux or any other aid that may hinder hermetic sealing.

Results:

The advantage of this processing method became clear once the customer who had an internal yield rate of just 30% transferred the process over to IJ Research were processing yields were increased to over 98%. Additionally X-Ray inspection performed on components for non-destructive evaluation shows that IJ Research’s soldering method was able to consistently obtain over 90% flow in the sealing area where the customer had previously been struggling to obtain over 50% flow. We were able to maximize yield and increase the assembly performance by applying our unique and highly specialized knowledge in establishing the most reliable and durable hermetic joints.

Background

Industry – Defense

Materials Used:

Graphite
IJ Research metallization formula

Requirement:

To metallize graphite for structural bonding of ceramic to graphite.

Challenges:

Graphite exhibits poor bonding to many materials. Often in braze processing, industry uses graphite tooling to mitigate the bonding of molten metal and parts can be easily removable from a graphite the tool. This is also the case for the glass sealing industry.

The goal was to metallize the graphite for subsequent high temperature brazing. For many years, the customer tried to develop a metallization using various materials and none of them showed any meaningful bonding strength to the graphite. During their subsequent brazing, the metallization came off or delaminated. The question was what material to be used and how to process.

Solution:

We needed to offer two features. First, a bonding mechanism of metallization over graphite. Second, to offer a braze ability in the subsequent processing at customer’s facility. After 6 months of R & D at IJ Research, we delivered prototypes for their qualification evaluation and their test was very successful in terms of the bonding strength and subsequent brazing. IJ Research has been a qualified source for their defense application ever since. The process has been well established with over two decades of regularly scheduled deliveries.