scholarly journals Preparation and Properties of Multilayer Ca/P Bio-Ceramic Coating by Laser Cladding

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 891
Author(s):  
Boda Liu ◽  
Zixin Deng ◽  
Defu Liu

In order to enhance the bioactivity and wear resistance of titanium (Ti) and its alloy for use as an implant surface, a multilayer Ca/P (calcium/phosphorus) bio-ceramic coating on a Ti6Al4V alloy surface was designed and prepared by a laser cladding technique, using the mixture of hydroxyapatite (HA) powder and Ti powder as a cladding precursor. The main cladding process parameters were 400 W laser power, 3 mm/s scanning speed, 2 mm spot diameter and 30% lapping rate. When the Ca/P ceramic coating was immersed in simulated body fluid (SBF), ion exchange occurred between the coating and the immersion solution, and hydroxyapatite (HA) was induced and deposited on its surface, which indicated that the Ca/P bio-ceramic coating had good bioactivity. The volume wear of Ca/P ceramic coating was reduced by 43.2% compared with that of Ti6Al4V alloy by the pin-disc wear test, which indicated that the Ca/P bio-ceramic coating had better wear resistance.

2017 ◽  
Vol 24 (Supp01) ◽  
pp. 1850009 ◽  
Author(s):  
H. X. ZHANG ◽  
H. J. YU ◽  
C. Z. CHEN ◽  
J. J. DAI

In order to improve the wear resistance of Ti alloys, different mass ratios of Ti-Si-Al powders were designed to fabricate hard phases reinforced intermetallic matrix composite coatings on the Ti-6Al-4V substrate by laser cladding. The corresponding coatings were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and high resolution transmission microscopy (HRTEM). The HV-1000 hardness tester and MM200 wear test machine were employed to test the hardness and the wear resistance of the composite coatings, respectively. The composite coatings mainly consisted of the reinforcements of Ti5Si3, Ti3AlC2 and Ti7Al5Si[Formula: see text] and the matrix of Ti3Al, TiAl, TiAl3 and [Formula: see text]-Ti. The micro-hardness of the Ti-35Al-15Si coating was from 956 HV[Formula: see text] to 1130 HV[Formula: see text], which was approximately 3–4 times of the substrate and the highest in the three samples. The wear rate of the Ti-35Al-15Si coating was 0.023[Formula: see text]cm3[Formula: see text][Formula: see text][Formula: see text]min[Formula: see text], which was about 1/4 of the Ti-6Al-4V substrate. It was the lowest in the three samples.


2019 ◽  
Vol 944 ◽  
pp. 473-479 ◽  
Author(s):  
Yu Sun ◽  
Vannghia Tran ◽  
Dao Zhang ◽  
Wen Bin Wang ◽  
Sen Yang

In this study, Cu/TiB2composite coating was in-situ prepared on 304 steel by laser cladding. This coating applies to hospitals, schools and some public places where cross infections happen more easily because of its good antimicrobial properties and abrasion resistance. Before laser cladding, pre-blend of Cu powder, Ti powder and B powder were undertaken by ball-milling in two different proportions (10% wt (Ti+B) and 20% wt (Ti+B)). And the atomic ratio of Ti and B was 1:2. After a series of experiments, the best parameters were achieved. They were laser power (950W), scanning speed (14mm/s) and spot diameter (3.8mm). Samples after laser cladding were characterized using optical microscopy, scanning electron microscopy and X-ray diffraction. The results showed that TiB2was fabricated in-situ. The dispersion degree of Cu was higher in the coating of 20% wt (Ti+B). The hardness of the 10% wt (Ti+B) coating was HRC57±4. With the increase of percentage of wt (Ti+B), the hardness of 20% wt (Ti+B) coating was HRC74±5. Both of them performed better than pure copper. Relative to pure copper, the abrasion resistance of Cu/TiB2composite coatings was more excellent. The results of antimicrobial experiments showed that, with the increase of percentage of wt (Ti+B), the antimicrobial properties were decreasing. But they still could to be considered favorable.


2021 ◽  
Vol 313 ◽  
pp. 15-21
Author(s):  
A.N. Gots ◽  
A.B. Lyukhter ◽  
Dmitry A. Kochuev ◽  
K.A. Frolov ◽  
I.V. Rumyantcev

One of the well-known methods for increasing wear resistance, especially for friction pairs, is surfacing wear-resistant materials on the working surfaces of mating parts [1, 2, 3]. Less expensive grades of steel can be used as the main material in the manufacture of parts, and the surfacing materials in this case must have increased characteristics: mechanical, corrosion and radiation resistance, heat resistance, wear resistance; good anti-friction properties, i.e. more expensive [4, 5]. This significantly reduces the cost of manufacturing or repairing parts, especially in mass production, since cheap grades of steel are used for their manufacture [5, 6]. Improvement of parts by gas powder laser cladding is carried out in shipbuilding, energy, oil and gas and mining industries, in the aviation industry and others. Note that although the method of coating appeared a long time ago, various methods of applying surfaced coatings are still being developed and refined [5,6]. In gas powder laser cladding, coatings are obtained by forcing the powder flow directly into the laser radiation zone [7, 8]. The powder particles are heated in the laser radiation zone and fall on the treated surface (substrate). It is known that the powder particles melt only after they hit the substrate [3, 4], but at the same time the surface layer of the base metal melts. After heating and melting the substrate, a liquid melt bath is formed, which, along with the molten powder, contains a significant part of the base metal components [7, 8]. The intensity of saturation of the surfacing metal with the substrate components is characterized by the proportion of the base metal in the cross section of the track, which is determined by the mixing ratio [9, 10, 11]. It is equal to the ratio of the area of the melted substrate to the sum of the areas of the melted substrate and the track as a percentage and depends on the cladding modes, which is determined after metallographic studies of the structure of protective coatings [8].


2017 ◽  
Vol 24 (4) ◽  
pp. 541-546 ◽  
Author(s):  
Hongxia Zhang ◽  
Huijun Yu ◽  
Chuanzhong Chen

AbstractThe composite coatings were fabricated by laser cladding Ni60A/B4C pre-placed powders on the surface of Ti-6Al-4V alloy for improving wear resistance and hardness of the substrate. In this research, the composite coatings were studied by means of X-ray diffraction, scanning electron microscope and energy dispersive spectrometer. The sliding wear tests were performed using MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there was a good metallurgical bond between the laser cladding coating and Ti-6Al-4V substrate. The composite coatings were mainly composed of the matrix of γ-Ni and a little Ni3Ti and the reinforcements of TiB2, TiC and CrB. The hardness of the sample of Ni60A-5B4C was approximately 2.5–3.5 times that of the Ti-6Al-4V substrate. The hardness of the sample of Ni60A-10B4C was 30% higher than that of sample 1. The wear resistance of samples 1 and 2 were 11 times and 10 times that of the substrate, respectively.


2015 ◽  
Vol 22 (03) ◽  
pp. 1550044 ◽  
Author(s):  
H. X. ZHANG ◽  
H. J. YU ◽  
C. Z. CHEN

The composite coatings were fabricated by laser cladding Al / TiN pre-placed powders on Ti –6 Al –4 V substrate for enhancing wear resistance and hardness of the substrate. The composite coatings were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The sliding wear tests were performed by MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there was a good metallurgical bond between the coating and the substrate. The composite coatings were mainly composed of the matrix of β- Ti  ( Al ) and the reinforcements of titanium nitride ( TiN ), Ti 3 Al , TiAl and Al 3 Ti . The hardness and wear resistance of the coatings on four samples were greatly improved, among which sample 4 exhibited the highest hardness and best wear resistance. The hardness of the coating on sample 4 was approximately 2.5 times of the Ti –6 Al –4 V substrate. And the wear resistance of sample 4 was four times of the substrate.


2020 ◽  
Vol 976 ◽  
pp. 9-14 ◽  
Author(s):  
Wei Zhang ◽  
Qiu Hong Feng ◽  
Wei Zhong Zhang

Aiming at the problem of poor high-temperature wear-resistance of rope clamp used in super-high speed elevators, the experiments of laser cladding to prepare carbide reinforced composite coating were made. nanoTiC powder, Ni-based alloy powder were used as cladding material. The microstructure and hardness of composite coating were tested by relevant equipments. The research results show that the composite coating is made up of TiC, Cr3C2, Fe3C and Fe-Ni-Cr-C HYPERLINK "javascript:void (0);" solid solution. When the content of TiC is 10%, 30%, the morphology of TiC is presented as dendrite-like and the morphology of HYPERLINK "javascript:void (0);" solid solution is presented as cellular-like. When the content of TiC is 50%, the morphology of TiC is presented as block-like, lath-like. There are some microcracks on grain boundaries. At the content of 30%, laser power 1.5KW, scanning speed 600mm/min, the laser cladding has no crack and hole. The average hardness of composite coating is 701HV0.2. Using this technology to the surface strengthening of elevator parts, the wear resistance and service life can be greatly improved.


Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 300 ◽  
Author(s):  
Haijiang Wang ◽  
Wei Zhang ◽  
Yingbo Peng ◽  
Mingyang Zhang ◽  
Shuyu Liu ◽  
...  

FeCoCrNi-Mo high entropy alloy/diamond composite coatings were successfully prepared by high speed laser cladding. A high scanning speed was adopted (>30 mm/s), and the effects of laser power, scanning speed, and diamond content on the microstructure and wear resistance of the composite coating were studied. The processing parameters of laser cladding had significant influence on the dilution ratio, graphitization of diamond, and wear resistance of the composite coatings. When the laser cladding parameters were 3000 W of laser power and the high scanning speed of 50 mm/s, the composite coating exhibited a uniform microstructure, the lowest dilution ratio, and the best wear resistance. The wear resistance of the composite coating was enhanced with the addition of diamond, but microcracks also increased. When the amount of diamond was 15 wt.%, the best combination of microstructures and wear resistance was obtained.


2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110131
Author(s):  
Gong Yuling ◽  
Wu Meiping ◽  
Miao Xiaojin ◽  
Cui Chen

All the time, the wear resistance of TC4 titanium alloy restricts its application in friction parts. In order to solve this problem, in this work, CeO2/Ni60A composite coatings (0, 1, 2, 3, 4 wt.% CeO2) were prepared on TC4 titanium alloy by laser cladding technology. The detection and characterization of the coatings were mainly carried out by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy-dispersive spectrometer, Vickers hardness test, and wear test. The results showed that appropriate proportion of CeO2 powder could effectively reduce the crack sensitivity of Ni60A coating on TC4 substrate. While the amount of CeO2 powder was 3wt.%, there were no obvious cracks, pores, and other defects in the coating. Coatings mainly consisted of Ti2Ni, TiC, TiB2, Ce2O3, and the substrate α–Ti. CeO2 has negligible influence on the composition of the phase, but it significantly increased the absorption rate of the powder to light, promoted the fluidity of the molten pool. Among five coatings, the average hardness of the 3Ce coating was the highest and the highest hardness value could reach 1163.7 HV0.3, which was 3.58 times higher than TC4 substrate, the friction coefficient was 0.307, and the wear rate was 1.11 × 10−5 mm3/N m, which reflected extremely high wear resistance performance. Adding an appropriate amount of CeO2 improved the microstructure of the coating, and realized the fine crystal strengthening of the coating.


2019 ◽  
Vol 46 (3) ◽  
pp. 0302005
Author(s):  
赵淑珍 Zhao Shuzhen ◽  
金剑波 Jin Jianbo ◽  
谢敏 Xie Min ◽  
许永波 Xu Yongbo ◽  
戴晓琴 Dai Xiaoqin ◽  
...  

2020 ◽  
Vol 27 (12) ◽  
pp. 2050021
Author(s):  
YUFAN SUN ◽  
HANGUANG FU ◽  
SHUANGYE CHEN ◽  
XUELONG PING ◽  
SHUTING SUN ◽  
...  

Based on the background of automotive mold surface strengthening, the effects of three different enhancements on the microstructure evolution, micro-hardness and wear resistance of laser cladding cobalt-based coatings were studied. The three reinforcing materials were Co45 alloy powder, Co45/8% B4C mixed powder and Co45/8% B4C/5% Cr3C2 mixed powder. They were respectively used to conduct laser cladding on the surface of die steel with preset powder method, with laser power of 2000[Formula: see text]W and scanning speed of 4[Formula: see text]mm/s. According to the test results, the hardness and wear resistance of the cladding coating were the best when Co45/8% B4C powder was added. In addition, the study also found that B4C reacted with Cr3C2 during laser cladding to eventually generate Cr2B. The CrB2 generated for the first time during the reaction was transformed into the most stable Cr2B with an orthorhombic Fddd symmetry due to its poor stability. Therefore, the sample with Co45/8% B4C/5% Cr3C2 mixed powder was affected with a slight decrease in microhardness and wear resistance.


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