Papers by Author: Zhan Lai Ding

Abstract: Indium Tin Oxide (ITO) conductive films are widely used to make Thin Film Transistor (TFT), Liquid Crystal Display (LCD), and Plasma Display Panel (PDP) as its high transmittance of visible light and conductivity. But now, most of the methods that used to prepare ITO conductive film must be conducted under vacuum condition and there are many problems in the economic benefits and production efficiency of these methods which limit their application. In this paper two ITO film prepared methods under non-vacuum condition are proposed: one is a matrix-injecting method, the other is a high voltage electro-spinning method. Some simple experiments and designs are executed to test the feasibility of the above two methods. The results shown that the above two methods are fit to prepare the ITO film, and the surface quality of initial ITO film made by the high voltage electro-spinning method is smooth and uniformity.

Abstract: The nano-scale indium tin oxide (ITO) particles are synthezed by liquid phase co-precipitation method under given conditions with solution of indium chloride, tin chloride and ammonia. The absolute ethyl alcohol or deionized water was used as solvent and the dodecylamine or hexadecylamine surfactant as a dispersant in the reaction system. The sample powder was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution electron microscopy (HRTEM). Based on the transmission electron micrograph， the influences of the two different solvents and the two different dispersants on the nanoparticle size and dispersion were studied respectively. The results shown that the ITO particles are finely crystallized body centered cubic structure. The particle size has distributed in 30nm to 90nm.

Abstract: In recent years, several electronics manufacturers have been working toward introducing lead-free solder and halogen-free print circuit boards (PCBs) into their products. The key drivers for the change in materials have been the impending environmental legislations, particularly in Europe and Japan as well as the market appeal of ‘green’ products. The reliability of the new materials is an important determinant of the pace of adoption. Fairly extensive mechanical fatigue reliability data is also available for micro-joining soldered joint such as Ball Grid Array (BGA) with tin-lead solder. However, similar data is not available for BGAs assembled with lead-free solder. Mechanical reliability is a critical indicator for phone and BGA survival during repeated keypress, and to some extent during drop. In this paper, the mechanical bend fatigue of BGAs with tin-lead and lead-free solders on halogen-free substrates are examined respectively. A tin-silver-copper alloy was used as lead-free solder due to its increasing acceptance, and the results were compared to those from samples assembled with Sn63Pb37 solder. The reliability was examined at both low cycle and high cycle fatigue. Results show that the mechanical bend fatigue reliability of BGA assemblies with lead-free solder is higher than that of BGA assembly with tin-lead solder. Cross section and failure analysis indicated two distinct failure modes - solder joint and PCB failure. A 3-D parametric finite element model was developed to correlate the local PCB strains and solder joint plastic strains with the fatigue life of the assembly. The intermetallic compoumd (IMC) of micro-joining joint interface was analysised in the future in order to study on the effect of IMC on the reliability.

Abstract: A semi-metallic stainless steel/carbon fiber reinforced PEEK-based friction material was developed in this paper. The composite was PEEK 19.63wt%, stainless steel fiber 7.57 wt%, carbon fiber 10.97 wt%, cashew 6.51 wt% and fillers 55.33%. The molding process was blending for about 30 seconds at higher speed, pre-heating at the temperature of 80
for 30min, molding at 320
and pressure 35Mpa for 3min/mm, then post-curing at the temperature of 80
for 30min , 150
for 30min270
for 30min320
for 180min. The results of abrasion test showed that the developed material N3 had higher and steady friction coefficient and low abrasion value. The SEM morphology study showed that the wear mechanism was particle abrasion at low temperature but adherence abrasion as well as particle abrasion occurred at higher temperature. The cohesive strength of the composite and the heat-resistant property of resin matrix were the key factors affected wear loss. The abrasion depended on the strength of transformed films and matrix.