scholarly journals Microstructure of Rhenium Doped Ni-Cr Deposits Produced by Laser Cladding

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2745
Author(s):  
Paweł Kołodziejczak ◽  
Dariusz Golański ◽  
Tomasz Chmielewski ◽  
Marcin Chmielewski

The addition of Rhenium up to 6% to Ni-Cr alloys can dramatically improve the corrosion and oxide resistance of deposited coatings at high operating temperatures. Ni-Cr+Re layers can be successfully produced using conventional powder metallurgy, high rate solidification (HRS), or magnetron sputtering methods. However, in industrial applications, high-performance deposition methods are needed, e.g., laser cladding. Laser cladding has several advantages, e.g., metallurgical bonding, narrow heat-affected zone (HAZ), low dilution, and slight thermal damage to the substrate. In this paper, a powder Ni-Cr composite with 1% (wt.) of Rhenium was produced, then deposited onto a steel substrate (16Mo3) by laser cladding to assess the micro and macrostructural properties of the obtained layers. Besides the macro and microscopic observations, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) microanalysis of the deposit and HAZ as well as microhardness measurements have been conducted. The microstructure observations revealed four subareas of HAZ gradually changing from the fusion line towards the base material. Maximum hardness occurred in the HAZ, mainly in areas closer to the clad/substrate interface, reaching up to 350–400 HV. No sudden changes in the composition of the deposit and the area of fusion line were observed.

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Robert Christie ◽  
Adrian Abel

Abstract This chapter provides an overview of the structural and synthetic chemistry, and the industrial applications, of dioxazine pigments, a small group of high performance organic pigments. The color violet (or purple) has frequently assumed a prominent position in history, on account of its rarity and cost. The natural colorant Tyrian purple and the first synthetic textile dye, Mauveine, are prime examples of this unique historical feature. CI Pigment Violet 23, also referred to as Dioxazine Violet or Carbazole Violet, is one of the most universally used organic pigments, by far the most important industrial pigment in the violet shade area. Dioxazine Violet is also unique as the dominant industrial violet pigment providing a brilliant, intense violet color and an excellent all-round set of fastness properties. The pigment has a polycyclic molecular structure, originally described wrongly as a linear arrangement, and later shown to adopt an S-shaped arrangement on the basis of X-ray structural analysis. Two other dioxazine pigments are of rather lesser importance. The synthesis and manufacturing route to CI Pigment Violet 23 is described in the review. Finally, a survey of the principal current applications of the individual dioxazine pigments is presented.


2016 ◽  
Vol 254 ◽  
pp. 290-295
Author(s):  
Iosif Hulka ◽  
Ion Dragoş Uţu ◽  
Viorel Aurel Şerban ◽  
Alexandru Pascu ◽  
Ionut Claudiu Roată

Laser cladding process is used to obtain protective coatings using as heat source a laser. This melts the substrate and the feedstock material to create a protective coating and provides a strong metallurgical bond with minimal dilution of the base material and reduced heat affected zone. In the present study a commercial NiCrSiFeB composition was deposited by laser cladding process using different parameters onto the surface of a steel substrate. The obtained coatings were investigated in terms of microstructure, hardness and wear behavior. The experimental results revealed that the laser power had a considerable influence on the wear resistance of NiCrSiFeB coatings.


2020 ◽  
pp. 2050046
Author(s):  
TIANWEI YANG ◽  
ZHAOHUI WANG ◽  
SHIHAI TAN ◽  
FU GUO

To increase the strength and wear resistance of material surfaces, various combinations of B4C and 80TiFe powder were mixed into a Fe60 self-fluxing alloy powder; the composite coatings reinforced by TiB2–TiC were successfully prepared on Q235 steel surfaces by laser cladding. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to study the microstructure and chemical and phase composition. Microhardness and wear testers were used to investigate the mechanical properties. The results show that the interfaces of composite coatings and substrate materials are excellent for metallurgical bonding. The block-like TiB2 particles and flower-like TiC particles are uniformly distributed in the cladding coating. When the mass fraction of the mixed powder is 30%, the average microhardness of the coating is approximately 1100 HV[Formula: see text], which is 50% higher than that without the mixed powder, and demonstrates the best wear with a performance twice as better as that of the substrate.


Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 544 ◽  
Author(s):  
Maider Muro ◽  
Josu Leunda ◽  
Garikoitz Artola ◽  
Carlos Soriano

The aim of this work is to evaluate the microstructural evolutions developed by mixing a corrosion-resistant and high-performance material with a high-hardness material in a coating obtained by laser-cladding technology. In this paper, five different mixtures of Inconel 625 alloy and AISI H13 steel powders have been deposited on a plate of 42CrMo4 steel using a 2.2 kW diode pumped Nd:YAG laser. The effect of adding tool steel to a Ni-based superalloy has been analyzed by the characterization of each cladded sample using optical microscopy and scanning electron microscopy (SEM). The precipitates observed in the samples have been analyzed by energy dispersive X-ray spectroscopy (EDS X-ray). SEM micrographs and EDS analysis indicate the existence of Laves phase. It has been observed that the presence of these precipitates is stabilized in a certain range of AISI H13 addition.


2012 ◽  
Vol 512-515 ◽  
pp. 639-642 ◽  
Author(s):  
Xiao Qin Guo ◽  
Jing Bo Chen ◽  
Xin Fang Zhang ◽  
Yong Kai Wang ◽  
Rui Zhang

Cu-TiB2 composite coatings were in-situ synthesized on the copper substrate by using a Nd: YAG laser. The microstructure of the coating and the bonding interface between the laser cladding layer and the substrate were studied by X-ray and SEM. The microhardness and the wear resisting property were tested. The results show that the TiB2 particles were well-proportioned and spherical existing in the coating layer, the bonding interface between the layer and substrate was metallurgical bonding. The microhardness reaches HV450 and the wear resistance is about 10 times as much as that of Cu substate.


2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Hongdong Li ◽  
Shaoheng Cheng ◽  
Jia Li ◽  
Jie Song

In the last decade, besides the breakthrough of high-rate growth of chemical vapor deposited single-crystal diamonds, numerous nanostructured diamond films have been rapidly developed in the research fields of the diamond-based sciences and industrial applications. The low-dimensional diamonds of two-dimensional atomic-thick nanofilms and nanostructural diamond on the surface of bulk diamond films have been theoretically and experimentally investigated. In addition, the diamond-related hybrid nanostructures of n-type oxide/p-type diamond and n-type nitride/p-type diamond, having high performance physical and chemical properties, are proposed for further applications. In this review, we first briefly introduce the three categories of diamond nanostructures and then outline the current advances in these topics, including their design, fabrication, characterization, and properties. Finally, we address the remaining challenges in the research field and the future activities.


2007 ◽  
Vol 330-332 ◽  
pp. 569-572 ◽  
Author(s):  
Sen Yang ◽  
Hau Chung Man

To accelerate the bone growth around a metallic implant and to achieve the mechanical characteristics needed for biomedical applications, a HA/Ti composite coating was produced on NiTi alloy substrate by laser cladding. The chemical compositions, microstructures and surface morphology of the cladded layer were analyzed using energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffractometry (XRD). The experimental results showed that an excellent metallurgical bonding between the coating and the substrate was obtained. Owing to decomposition of HA under irradiation of high power laser, the microstructures in bioceramics coating were mainly composed of CaO, CaTiO3, Ti4P3, and HA phases. In vitro experimental result showed that HA/Ti composite coating made the bioactivity of NiTi alloy improve remarkably, which would promote the bone growth and could restrain Ni ion releasing from NiTi alloy.


2007 ◽  
Vol 361-363 ◽  
pp. 697-700
Author(s):  
Ying Chun Wang ◽  
Yan Min Li ◽  
Zhen Min Xu ◽  
Qi Lin Deng ◽  
Jian Guo Li ◽  
...  

Undesirable phase and microstructure formation, and poor HAP/metal bonding strength restrict the fabrication technique to obtain HAP and other calcium phosphate ceramic coatings. In this paper a bioceramic composite coating, which includes HAP andβ-Ca2P2O7, was obtained by laser cladding with pre-depositing mixed powders of CaHPO4·2H2O and CaCO3 directly on the 316L stainless steel metal substrate. The phases, microstructure and bonding feature of the bioceramic composite coating are characterized by X-ray diffraction(XRD), scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS). The microstructure of the coating consists of minute granular HAP that is distributed among the overlapped club-shapedβ-Ca2P2O7. Uniform presences of Ca, P and O in bioceramic composite coating supplie necessary elements for the synthesis of HAP andβ-Ca2P2O7. Diffusions inwards of P and O into alloying layer help form the chemical metallurgical bonding and composition gradient distributions are present. a chemical metallurgical bonding was formed between the bioceramic composite coating and metal substrate.


2013 ◽  
Vol 744 ◽  
pp. 440-444
Author(s):  
Jing Liu ◽  
Xiao Li Gao ◽  
Yang Xu ◽  
Gang Ling

The non-smooth surfaces on 45 steel were prepared by laser cladding with KF-300A alloy powder on the basis of the bionic non-smooth morphology of shark scales. The rib-type coatings were composed of hot-rolled steel 45 and clad layers containing hard phases such as WC/W2C. In this paper, the influence of laser power and defocusing distance on the quality of cladding layer were investigated. The microstructure of the coatings was analyzed by scanning electron microscopy, with attached energy dispersive spectroscopy microprobe, and by X-ray diffraction. SEM inspection of the samples showed that all coatings exhibited similar phases in their microstructure, but the phases presented differ in morphology, size and distribution. Dilution and interaction zone of the coatings were also discussed in this paper. The results showed that the non-smooth coatings were crack-free and had a good metallurgical bonding with 45 steel trenches with a low dilution under the optimum laser conditions (P=700 W, f =14 mm, V=3 mm/s, continuous powder feeding voltage 2.1 V, nitrogen protection).


2014 ◽  
Vol 548-549 ◽  
pp. 289-293 ◽  
Author(s):  
Mum Wai Yip ◽  
Stuart Barnes ◽  
Ahmed A.D. Sarhan

The objective of this study was to develop clad layer by producing a Silicon Carbide (SiC) particle reinforced Metal Matrix Composite (MMC) using the iron based alloys (P25) as the matrix material. Direct laser cladding was carried out by melting the clad materials and depositing them onto a mild steel substrate. A two gravity feed system was used in this study which contained of SiC particles and iron based powder as separate powders. The intention was to melt the iron based powder and incorporate the SiC particles. Decomposition of SiC particles was observed and only a few SiC particles were found in the clad matrix. Microhardness results showed that laser clad layer had higher hardness which more than 1000 HV and hence potentially better wear resistance that base material. However, most of the SiC had evaporated which created porosity in the melt pool due to the decomposition of SiC and the resultant gas which was trapped in clad layer did not have enough time to escape from the melt pool due to the rapid solidification. Therefore, a blown powder technique is recommended for overcome this problem.


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