scholarly journals The Enhancement Effect of Salt Bath Chromizing for P20 Steel

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Zihao Wei ◽  
Chundong Zhu ◽  
Lianpu Zhou ◽  
Liming Wang
Keyword(s):  
Thermal Diffusion ◽  
Chromium Carbide ◽  
Salt Bath ◽  
Chromium Coating ◽  
Material Surface ◽  
Enhancement Effect ◽  
Carbide Coating ◽  
Hardness Tester ◽  
Chromium Plating ◽  
Chromium Carbide Coating

The TD (Thermal Diffusion) salt bath process is used to obtain a super hard carbide coating on the material surface by utilizing the mechanism of metal thermal diffusion. In this paper, chromium carbide coating was prepared on P20 hot-pressing die steel by the TD salt bath chromizing process. Characterization of the modified surface layer was made by means of scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), a micro-hardness tester and an automatic scratch tester. The influence rules of different salt bath times and temperatures on the growth thickness of the cladding layer were explored through experiments, and the optimum salt bath process scheme was determined as a temperature of 960 °C and time of 6 h. The chromium carbide coating with a thickness similar to that of chromium plating was prepared, and the average thickness of the coating was about 8–10 μm. The results showed that hardness and bonding strength of chromium carbide coating are higher than that of electroplated chromium coating. The combination of chromium carbide coating and matrix is metallurgical, while the electroplated chromium coating is physical. Immersion corrosion test results show that both coatings have good corrosion resistance in a 65% nitric acid solution.

scholarly journals Wear and Corrosion Resistance of Chromium–Vanadium Carbide Coatings Produced via Thermo-Reactive Deposition

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 215 ◽  
Author(s):  
Fabio Castillejo ◽  
Jhon Olaya ◽  
Jose Alfonso
Keyword(s):  
Corrosion Resistance ◽  
Chromium Carbide ◽  
Vanadium Carbide ◽  
Electrochemical Impedance ◽  
Salt Bath ◽  
Carbide Coating ◽  
Reactive Deposition ◽  
Chromium Carbide Coating ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

Chromium carbide, vanadium carbide, and chromium–vanadium mixture coatings were deposited on AISI D2 steel via the thermo-reactive deposition/diffusion (TRD) technique. The carbides were obtained from a salt bath composed of molten borax, ferro-chrome, ferro-vanadium, and aluminum at 1020 °C for 4 h. Analysis of the morphology and microstructure of the coatings was done via scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The hardness of the coatings was evaluated using nano-indentation, and the friction coefficient was determined via pin-on-disk (POD) testing. The electrochemical behavior was studied through potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS). The XRD results show evidence of the presence of V8C7 in the vanadium carbide coating and Cr23C6 and Cr7C3 in the chromium carbide coating. The hardness value for the vanadium–chromium carbide coating was 23 GPa, which was higher than the 6.70 ± 0.28 GPa for the uncoated steel. The wear and corrosion resistance obtained was higher for the niobium–chromium carbide coating, due to the nature of the ceramic carbide produced.

A Study on Effect of Beginning V Concentration in TD Process

2014 ◽  
Vol 624 ◽  
pp. 134-137
Author(s):  
Shi Nan Li ◽  
Hui Chen ◽  
Yan Jie Zhang ◽  
Zhang Yu Gao ◽  
Li Zhen Liu ◽  
...  
Keyword(s):  
Thermal Diffusion ◽  
Salt Bath ◽  
Reducing Agent ◽  
Micro Hardness ◽  
Hardness Tester ◽  
Vital Factor ◽  
Vickers Micro Hardness

Procedures of thermal diffusion (TD) process are carried out on two specimens of Cr12MoV steel using the same salt bath formula. For the two specimens, the beginning V concentration, V concentration at the time specimen is added, are different, the level of which is controled by changing the interval between the specimen are added and the time reducing agent of Al meeting with vanadizing source of V2O5. The interval for Specimen 1 and Specimen 2 are 10 and 30 minutes respectively. Consequently, different changes are happened on the surface of the substrates. The microstructures of coatings are observed by optical metallographic microscope and SEM/EDS, the hardness are tested by Vickers micro-hardness tester. Results show that: VC coating formed on Specimen 2 is of better performances than Specimen 1, microhardness of Specimen 2 reaches as much as 2400HV. It can be concluded that level of V concentration at the beginning of TD process is a vital factor for the forming of VC layer.

Sign in / Sign up

Export Citation Format

Share Document