Sliding Wear Study of Flame Sprayed Co-Base Powder Coatings

Commercially available Co-base powder was modified with the addition of 10 wt. percentage WC which was further modified with 5 and 10 wt. percentage CrC addition in order to obtain three coatings namely Co+10 wt. percentage WC, Co+10 wt. percentage WC+5 wt. percentage CrC and Co+10 wt. percentage WC+10 wt. percentage CrC. The coatings were deposited by flame spraying process. The microstructure of these coatings mainly showed eutectic containing Co with almost same amount in three coatings. Other phases such as W dominated and Cr dominated carbides were also observed. The 10 wt. percentage CrC coating showed the highest Vickers hardness and lowest wear rate. The coefficient of friction was also observed low in the 10 wt. percentage CrC coating as compared with other coatings

Effect of rare earth on microstructure and wear behaviour of Ni based microwave clad

564-572In the present investigation microwave energy has been utilized to develop wear resistant Ni-based clad without Nd2O3 (unmodified coating) and with addition of Nd2O3 (modified coatings) in varying wt. % of 1-3. The clads have been developed using domestic microwave oven at frequency of 2.45 GHz and power 900 W for duration of 360 s. The unmodified and modified clads have been characterized in terms of microstructure, XRD, microhardness and two body abrasive wear. The average thickness of developed clads has been measured as 1.0 mm approximately. A two body abrasive wear behaviour of unmodified and modified coatings at sliding speed of 36 m/min & 72 m/min with abrasive grit size of 220 & 600 has been investigated. The results revealed a better abrasive wear resistance at lower sliding speed and fine grit size. Further, the best results of microstructure, formation of hard phases, improved microhardness and wear resistance have been shown by the samples having coating composition as 3 wt. % of Nd2O3

Effect of rare earth on microstructure and wear behaviour of Ni based microwave clad

In the present investigation microwave energy has been utilized to develop wear resistant Ni-based clad without Nd2O3(unmodified coating) and with addition of Nd2O3 (modified coatings) in varying wt. % of 1-3. The clads have beendeveloped using domestic microwave oven at frequency of 2.45 GHz and power 900 W for duration of 360 s. Theunmodified and modified clads have been characterized in terms of microstructure, XRD, microhardness and two bodyabrasive wear. The average thickness of developed clads has been measured as 1.0 mm approximately. A two body abrasivewear behaviour of unmodified and modified coatings at sliding speed of 36 m/min & 72 m/min with abrasive grit size of 220& 600 has been investigated. The results revealed a better abrasive wear resistance at lower sliding speed and fine grit size.Further, the best results of microstructure, formation of hard phases, improved microhardness and wear resistance have beenshown by the samples having coating composition as 3 wt. % of Nd2O3

Xanthogranulomatous salpingitis - pathological aspect of chronic pelvic inflammatory disease in a patient with sigmoid diverticulitis

A case of Xanthogranulomatous salpingitis in 55yrs old women with sigmoid diverticulitis is presented. Xanthogranulomatous inflammation is an uncommon form of chronic inflammation which affects various organs and is destructive in nature. This inflammatory process is characterized by massive infiltration of the tissues by lipid laden histiocytes admixed with lymphocytes, plasma cells and polymorphonuclear leucocytes. Pelvic inflammatory disease is the main etiology. This could have possibly resulted in xanthomatous process in our case leading to xanthogranulomatous salpingitis

Friction stir welding of copper: Processing and multi-objective optimization

709-716Non-ferrous metals are difficult to weld as compared to the ferrous metals. Copper is one of the non-ferrous metals using worldwide in different manufacturing and other metal processing industries. This paper focuses on the processing of copper under friction stir welding (FSW) and the study of mechanical properties of friction stir welded (FSWed) copper joints. Different parameters of FSW have been studied with the help of L9 orthogonal array (OA). Rotational speed and traverse speed of the tool with three different tool materials have undergone for the parametric optimization. Tensile strength and impact strength have been optimized using the grey relational method. Results show a significant effect of parameters on responses. Finally, it has been concluded that the grey relational method is a robust method to optimize the combined set of responses in a single attempt. From results, it has been observed that the higher rotational speed and lower traverse speed with H13 tool material give better results for mechanical properties. Analysis of variance (ANOVA) has been used to find the percentage contribution of each parameter on mechanical properties. P-value has been found less than 0.05 which shows that the effect of each selected parameter on the result is significant. Microstructure study has been performed on scanning electron microscopy (SEM) and the change in grain size within the weld zone has been observed

Friction stir welding of copper: Processing and multi-objective optimization

Non-ferrous metals are difficult to weld as compared to the ferrous metals. Copper is one of the non-ferrous metals using worldwide in different manufacturing and other metal processing industries. This paper focuses on the processing of copper under friction stir welding (FSW) and the study of mechanical properties of friction stir welded (FSWed) copper joints. Different parameters of FSW have been studied with the help of L9 orthogonal array (OA). Rotational speed and traverse speed of the tool with three different tool materials have undergone for the parametric optimization. Tensile strength and impact strength have been optimized using the grey relational method. Results show a significant effect of parameters on responses. Finally, it has been concluded that the grey relational method is a robust method to optimize the combined set of responses in a single attempt. From results, it has been observed that the higher rotational speed and lower traverse speed with H13 tool material give better results for mechanical properties. Analysis of variance (ANOVA) has been used to find the percentage contribution of each parameter on mechanical properties. P-value has been found less than 0.05 which shows that the effect of each selected parameter on the result is significant. Microstructure study has been performed on scanning electron microscopy (SEM) and the change in grain size within the weld zone has been observed

Intestinal endometriosis: a diagnostic dilemma

Background: Endometriosis is a benign gynaecological condition that causes significant morbidity to women of reproductive age group. It uncommonly affects the gastrointestinal tract and acute bowel obstruction is a rare manifestation.Methods: A retrospective observational study was conducted on eight patients.Results: In three patients (37.5%), small intestinal involvement was seen, and colon was involved in five patients (62.5%). One (12.5%) patient presented with complete bowel obstruction while in others partial obstruction of the intestine was seen.Conclusions: Intestinal endometriosis is a diagnostic challenge and should be considered in young menstruating women with gastrointestinal symptoms. Intestinal endometriosis is the most common extra-pelvic site and it is found in 12% of women with endometriosis. The true incidence of endometriosis causing bowel obstruction is unknown. Pre or intraoperative sigmoidoscopy may prove helpful in ruling out malignancy. The gold standard for diagnosis is laparoscopy and biopsy, which allows a full assessment of the pelvis as well as surgical resection if required. The management of endometriosis is an integrated approach of both medical and surgical therapy. Bowel resection is usually undertaken if there are features of obstruction or bleeding, and if there is suspicion of malignancy

A study on the effect of different chemical routes on functionalization of MWCNTs by various groups (-COOH, -SO3H, -PO3H2)

Pristine multiwall carbon nanotubes [MWCNTs] have been functionalized with various groups (-COOH, -SO3H, -PO3H2) using different single- and double-step chemical routes. Various chemical treatments were given to MWCNTs using hydrochloric, nitric, phosphoric, and sulphuric acids, followed by a microwave treatment. The effect of the various chemical treatments and the dispersion using a surfactant via ultrasonication on the functionalization of MWCNTs has been studied. The results obtained have been compared with pristine MWCNTs. Scanning electron microscopy, energy dispersive X-ray [EDX] spectroscopy, and transmission electron microscopy confirm the dispersion and functionalization of MWCNTs. Their extent of functionalization with -SO3H and -PO3H2 groups from the EDX spectra has been observed to be higher for the samples functionalized with a double-step chemical route and a single-step chemical route, respectively. The ID/IG ratio calculated from Raman data shows a maximum defect concentration for the sample functionalized with the single-step chemical treatment using nitric acid. The dispersion of MWCNTs with the surfactant, Triton X-100, via ultrasonication helps in their unbundling, but the extent of functionalization mainly depends on the chemical route followed for their treatment. The functionalized carbon nanotubes can be used in proton conducting membranes for fuel cells

Cryogenic Processing of HSS M2: Mechanical Properties and XRD Analysis

The purpose of this study was to reveal the changes in properties of deep cryogenic treatment (DCT) processed high speed steel, in comparison to conventional heat treatment for secondary hardness. Tool properties were assessed in terms of hardness, and tensile strength. Statistically significant enhancement in the mechanical properties was observed. Cryogenic processing of HSS tool steel eliminated the retained austenite, and hence increased the hardness of the material. This treatment initiated nucleation sites for precipitation of large numbers of very fine carbide particles.Tensile values for cryogenically treated HSS samples can be attributed to the fact that the tool becomes more brittle after the treatment. XRD analysis illustrated the contraction in lattice of martensite and austenite. Deep cryogenic treatment practically removed all traces of austenite in the sample. The superior performance of cryogenically treated HSS can be attributed to the transformation of almost all retained austenite into martensite, a harder structure and precipitation of fine and hard carbides

Dry sliding wear investigation of Al6082/Gr metal matrix composites by response surface methodology

The effect of graphite particles on the dry sliding wear behaviour of Al6082 alloy composites produced by conventional stir casting method has been investigated. The percentage of reinforcement was varied from 0% to 12% in a step of 3. The result showed that with the addition of graphite particles micro- and macro-hardness reduced by 11.11% and 10.44%, respectively. The tribological behaviour of composites was investigated by pin on disc apparatus. Percentage reinforcement, load, sliding speed and sliding distance were taken as the process variable. Response surface methodology has been used to plan and analyze the experiment. Results showed that sliding distance is the most influential factor and load is the factor which affects the wear least