The Hong Kong Polytechnic University

The Chinese University of Hong Kong

Guangdong University of Technology

Tai Man Yue

Chak Yin Tang

Su Ping Bao

Kang Cheung Chan

Chi Pong Tsui

Jiang Wen Liu

Da-zhu Chen

Yuen Yee Chan

Yujiao Chen

Zhichao Liu

Kam Po Wong

Zhongning Guo

A new ultrasonic aided laser joining method (UAL) for bonding dissimilar materials has been developed. The method is capable of eliminating the laser-induced bubbles at the bonding faces and to improve the joint strength over that of the conventional laser-assisted metal and plastic joining method (LAMP). Some experiments on joining titanium to polyethylene terephthalate have been conducted to show the superiority of UAL over LAMP. The results showed that the joint strength, measured in terms of failure load, was significantly increased when ultrasonic vibration was employed during laser joining. For the LAMP joined specimens, fracture normally occurred at the metal-plastic interface, whereas for the UAL joined specimens, fracture normally occurred in the parent plastic part. The improvement in joint strength is mainly due to the elimination of pores in the resolidified plastic. In addition, ultrasound vibration promotes chemical bonding between the plastic and metal parts, and this is supported by the XPS results.

Method of laser joining of dissimilar materials with ultrasonic aid

A new electrospark deposition (ESD) method and related system are provided in the present invention based on the use of a magnetized electrode, namely magnetic-aided ESD (M-ESD). In particular, the present invention uses a magnetized electrode (either magnetized by an electro-magnet or being a permanent magnet) to attract fine coating powders at the tip thereof which acts as a soft brush to coat on intricate surface profiles. Accordingly, the method of the present invention is able to provide a soft contact between the magnetized anode and the workpiece to be coated or manipulated. The present invention is useful in various surface engineering applications in the fields of aeronautical (e.g. restoration and repair of damaged aircraft turbine blades), nuclear reactors, military engineering, and in medical industries. As compared to conventional ESD, the present invention can address complicated surface geometries and internal surfaces while the cost can be significantly lowered by using inexpensive components and simplified method steps.

Magnetic-aided electrospark deposition

A method of fabricating a porous metal-based biomaterial, the method includes dispersing microwave susceptors into organic solvent to form a homogeneous suspension, dispersing bioactive fillers into organic solvent to form a homogeneous solution, mixing metal powder with the homogeneous solution and the homogeneous suspension to form a mixture, cold-pressing the mixture into a compact with predefined shape and size, placing the compact in a sintering container, and emitting microwave to heat the compact and remove the organic solvent resided in the compact at the same time.

Rapid fabrication of porous metal-based biomaterial by microwave sintering

A method of fabricating silicone composite with a layer of antimicrobial coating, the method includes forming an antimicrobial mixture by adding a calculated amount of antimicrobial agent to a solution of water and alcohol, depositing the antimicrobial mixture in a container with a thickness of 0.1 &#x3bc;m to 10 &#x3bc;m, evaporating the water and alcohol of the antimicrobial mixture to form the layer of antimicrobial coating, adding silicone resin on top of the layer of antimicrobial coating and allow the silicone resin to permeate and crosslink with the layer of antimicrobial coating and removing the silicone composite with the layer of antimicrobial coating from the container.

Method for fabrication of silicone composite with antimicrobial coating

It is known to apply a pulse current during electrodeposition of nickel. In the invention, pulse current waveforms have ramp-down spikes leading to improvements in surface finishes of electroforms created by the process.

Process for making nickel electroforms

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Hong Kong, China

Tai Man Yue