The Study Of Electroless Plating Iron Coating On Titanium Hydride That Be Used For Making Foamed Aluminium

Aluminum foam is a kind of new engineering material with special mechanical，electrical and acoustic property. As the most common metal foam materials，it has agreat potential application in the automotive industry， aerospace industry，construction industry and many other fields. There are many methods of preparingaluminum foam，while the easiest way is the melt foaming technique.The mostcommon foaming agent of preparing aluminum foam is hydrogenated titanium. Dueto the high temperature of the molten aluminum，TiH2will decompose quickly. Thus，it is difficult to control the speed of decompose of the foaming agent to obtain anuniform porosity aluminum foam. Property of aluminum foam depends on the sizeand uniformity of the pores. It is necessary to delay the decomposition of titaniumhydride by some methods.In this paper，the surface of hydrogenated titanium particles was coated with ironby electroless plating. Owing to iron does not react with the molten aluminum at hightemperature，so it can delay the decomposition of hydrogenated titanium and lengthenthe stirring time. Hydrogenated titanium can disperse evenly in the moltenaluminum，which contributed to obtain aluminum foam with uniform pores.In this paper，the surface of the copper was coated with iron by electroless platingfirstly. Through the orthogonal experiments，the influence degree of various factors onthe electroless plating iron is as follows：pH value，temperature，the concentration ofreducing agent，the concentration of lord salt. In order to explore the influence ofsingle factor on the electroless plating iron，the paper studied the influence on thegestating time，plating effect and the plating speed of electroless plating iron.Thesefactors contain temperature，pH value，concentration of ammonium ferrous sulfate，concentration of sodium borohydride，concentration of complexing agent，etc.Throughthe comparison，the optimum parameter for electroless plating iron was determinedfinally.Through the Metallurgical，SEM and XRD analysis on the surface of copperthat was coated with iron，the result indicated that the surface of copper was covered by iron completely. The best craft was carried out for titanium hydride powder. Dueto powder had a large specific surface area，this paper also studied the influence ofloading capacity on electroless plating iron. Results showed the coated effect waswell when the loading capacity of the powder was between3.0and4.5g/L. This paperalso analysed titanium hydride powder coated with iron by Scanning ElectronMicroscope analysis(SEM) and Energy Dispersive Spectrometer analysis(EDS). Theresearch showed the coated effect of powder was very well.The mass loss curves of the titanium hydride powder which was coated anduncoated with iron were investigated by thermogravimetric analysis from roomtemperature to700℃．The result indicated that the quality of the original titaniumhydride powder declined rapidly between550℃and600℃． However， thehydrogenated titanium powder coated with iron can improve the decompositiontemperature of hydrogenated titanium.The quality of hydrogenated titaniumcomposite powder decline rapidly between600℃and650℃．The result showed thatthe iron layer covered on the surface of hydrogenated titanium helped to delay thedecomposition of titanium hydride．The titanium hydride which was coated and uncoated with iron were prepared tomake the aluminum foam eventually，respectively. By comparison，the aluminumfoam which prepared from titanium hydride was coated with iron had a larger amountof pore，the dispersion of pore was more unform.