Integrated Micro Sensors Inc has developed an innovative pulsed laser technology based process for bonding very dissimilar materials, such as metals to ceramics or glass.
Houston, TX (PRWEB) April 04, 2015 -- Problems associated with the durability of bonds between very dissimilar materials stem from fundamental differences in the coefficients of thermal expansion and thermal conductivity. For example, ceramic or glass have relatively low coefficients of thermal expansion (CTE) compared to metals. The thermal conductivities in most cases are very different too, which actually adds to the problem. The material’s surface chemistry also greatly affects the soldering, brazing, and even the adhesive bonding processes.
An innovative technology developed at Integrated Micro Sensors Inc (IMS) allows for achievement of a drastic improvement of the bonding process between various metals and glass or ceramics. Dramatic increase in the bond strength in the metal/solder/ceramic or glass, metal/brazing alloy/ceramic or glass, or metal/adhesive/ceramic or glass interfaces is based on laser-assisted fabrication of Micro Column Arrays (MCA) on the surface of the metal and/or ceramic or glass surfaces subjected to bonding prior to the soldering, brazing, or adhesive bonding process. Typical scanning electron micrographs of MCA generated by laser ablation on stainless steel, titanium, and SiC ceramic are shown in Figures 1(A), 1(B), and 1(C), respectively, of the attachment.
MCA technology provides several advantages for the drastic improvement of bonds between any similar and dissimilar materials. First, mechanical strength increases due to the interlocking of the brazing (solder or adhesive) material between the micro columns. Second, the bond strength increases due to the increase of bonding specific surface area by more than an order of magnitude. Third, stability increases due to the inherent elasticity of the micro cones during a deformation that can occur due to stresses induced by differences in thermal expansion between the material and adhesive or braze or under shear stress (Figure 2 of the attachment). Fourth, increase in the bond durability occurs because of the repeated bend contours of the surface preventing hydrothermal failure. Fifth, wettability of the material surface significantly improves due to (i) a highly developed surface morphology at the micro and submicron level, and (ii) changes in local chemistry due to surface oxidation that could be beneficial to promoting a stronger bond. Sixth, the MCA technology is efficient, highly reproducible, environmentally safe, and can be applied virtually to any solid state material. Seventh, the MCA technology is highly scalable to large areas and minimum processing times, as the MCA fabrication efficiency is generally proportional to the average laser power. Commercial lasers with powers up to 5 kW are currently used for cutting of large area (several feet) materials.
IMS has already demonstrated improvement of bond strength between several similar and very dissimilar materials by using the MCA technology [1-3]. MCA processing in these efforts was performed by using a pulsed Nd:YAG laser emitting at a wavelength that is well absorbed by metals and most of ceramic materials. In order to process glass materials, transparent to visible and IR laser light, UV excimer lasers can be used. In addition, the material’s surface chemistry can be tailored by processing the MCA structures in gaseous or liquid ambient that contains necessary specific precursors.
The “know how” on this technology owned by IMS is described in an US patent [4] that has been recently issued on this application . If your company is interested in this remarkable technology, please contact Dr. David Starikov at: dstarikov(at)imsensors(dot)com, or by phone at: 713-748-7926. For more information about IMS, please visit: http://www.imsensors.com.
REFERENCES:
[1] “Enhancement of adhesive joint strength by laser surface modification.” E.G. Baburaj, D. Starikov, J. Evans, G.A. Shafeev, and A. Bensaoula. International Journal of Adhesion & Adhesives, 27, 268–276 (2007
[2]“Improved Nanoreinforced Composite Material Bonds with Potential Sensing Capabilities”. David Starikov, Clyde A. Price, Michael S. Fischer, Abdelhak Bensaoula, Farouk Attia, Thomas A. Glenn, and Mounir Boukadoum., Sensors & Transducers Journal, ISSN 1726-5479, Vol. 13, 117 (2012).
[3]“Improvements in Bonding of Silicon Carbide Ceramic to Metals”. D. Starikov, R. Pillai, T. Glenn, J. Gandhi, A. Price, R. Delaney, A. Bensaoula. International Journal of Materials Engineering, 4(6): 196-202 (2014).
[4] “Method of bonding Solid Materials”. David Starikov and Abdelhak Bensaoula. US Patent 8,962,151 (2015).
David Starikov, Integrated Micro Sensors Inc, http://www.imsensors.com, +1 713-748-7926, [email protected]
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