Effects of direct current field on powder pack aluminising

Abstract

Direct current field (DCF) has been applied on an aluminising specimen and powder aluminising agents to overcome conventional powder pack aluminising (CPA)'s shortcomings of high treating temperature, long soaking time and low efficiency in utilising aluminising media. The specimen in the shape of plate or tube was taken as cathode of the DCF. The anode in the shape of plate or column paralleled to the specimen. Effects of DCF on CPA have been studied. The treated case's microstructure, phase, thickness and oxidation resistance have been investigated. The results show that DCF has the function of enhancing aluminising with great energy saving, even at a temperature below 750uC. The aluminised case endows plain carbon steel with superior resistance to oxidisation in air at a high temperature of 850uC. Mechanisms of DCF's effects to CPA have been proposed, which were discussed from two aspects of the DCF's thermal and nonthermal effects to the aluminising process.

Effect of D.C. electric field on salt bath nitriding for 35 steel and kinetics analysis

“…In this study, based on the enhancement effect of direct current (D.C.) electric field on powder-pack thermo-chemical treatment [16][17][18][19] D.C. electric field was developed. This technology was carried out by applying D.C. electric field between the two electrodes in the nitriding salt bath.…”

Kinetic analysis of direct current field enhanced salt bath nitriding

“…Based on the enhancement effect of direct current field (DCF) on powder pack thermochemical treatment, 10,11 a novel rapid salt bath nitriding technology enhanced by DCF was developed. This technology was carried out by applying DCF between the two electrodes in the nitriding salt bath.…”

Alternating current field assisted pack boriding to Fe2B coating

“…FeB formed by electrochemical boriding was transformed to Fe 2 B by a subsequent homogenisation treatment in the same electrolyte for an additional time. Employing direct current field can greatly accelerate pack boriding as well as alumunising with energy saving,13 – 16 but the boride coating is a dual phase one. However, no report has been found that produces a single phase Fe 2 B coating directly by pack boriding in a quick and economic way.…”