Adherent diamond coatings on cemented tungsten carbide substrates with new Fe/Ni/Co binder phase

WC-Co hard metals continue to gain importance for cutting, mining and chipless forming tools. Cobalt metal currently dominates the market as a binder because of its unique properties. However, the use of cobalt as a binder has several drawbacks related to its hexagonal close-packed structure and market price fluctuations. These issues pushed the development of pre-alloyed binder powders which contain less than 40 wt.% cobalt. In this paper we first report the results of extensive investigations of WC-Fe/Ni/Co hard metal sintering, surface pretreating and deposition of adherent diamond films by using an industrial hot filament chemical vapour deposition (HFCVD) reactor. In particular, CVD diamond was deposited onto WC-Fe/Ni/Co grades which exhibited the best mechanical properties. Prior to deposition, the substrates were submitted to surface roughening by Murakami's etching and to surface binder removal by aqua regia. The adhesion was evaluated by Rockwell indentation tests (20, 40, 60 and 100 kg) conducted with a Brale indenter and compared to the adhesion of diamond films grown onto Co-cemented tungsten carbide substrates, which were submitted to similar etching pretreatments and identical deposition conditions. The results showed that diamond films on medium-grained WC-6 wt.% Fe/Ni/Co substrates exhibited good adhesion levels, comparable to those obtained for HFCVD diamond on Co-cemented carbides with similar microstructure

A Raman study of diamond film growth on Co-cemented tungsten carbide

Phase purity and crystallinity of diamond films grown by hot filament chemical vapor deposition on ISO-grade K10 cemented carbide [94.2 weight percent (w/o) WC-5.8 w/o Co] were studied by Raman spectroscopy as a function of substrate temperature, gas phase composition, and substrate pretreatments. High-quality diamond films were grown using 0.5% CH4/H-2 in a rather narrow range of substrate temperatures (750 to 760 degrees C). In all the deposited coatings, the first-order Raman band of diamond is detected at 1337 cm. This fact indicates that a 2 GPa residual compressive stress is present in the diamond phase. The linewidth of the diamond Raman peak increases with deposition temperature. This effect has been ascribed to a higher density of defects in diamond crystallites. It has been observed that Co removal from the substrate surface by wet chemical etching before deposition is less effective than a careful selection of deposition parameters to reduce the codeposition of nondiamond carbon phases. This finding has been attributed to the fast diffusion of the binder from the bulk to the substrate surface, even for the etched substrates

Toward greener synthesis of WC powders for cemented tungsten carbides manufacturing

Tungsten carbide (WC) is the most important tungsten compound, and the main component of WC-Co cermet composites. WC-Co are widely used engineering materials due to the combination of high hardness and strength of tungsten carbide with the toughness and plasticity of the metallic binder. The direct synthesis of WC from tungsten concentrate containing ∼70% WO3 has been achieved by carbothermic reduction. Mineral/carbon black mixtures were prepared by planetary ball milling and subjected to annealing at 1150 °C in flowing Ar. Specific leaching treatments have been developed to remove foreign phases and obtain pure WC powders. This new process allows about 50% energy saving, -34% CO2 emissions, and significantly lower amounts of industrial waste, with respect to the classical hydrometallurgical tungsten extraction and subsequent pyrometallurgical WC synthesis, widely used in tungsten industry. WC powders obtained by carbothermic reduction of the mineral were employed to prepare sintered WC-8 wt %Co samples that showed high density (>99%), hardness (1490 HV), and toughness (14.6 MPa·m1/2). These findings demonstrate, for the first time, that the carbothermic reduction of tungsten concentrates does represent a viable process for energy efficient and sustainable synthesis of WC powders to be used in the production of cemented carbides

Incidence and clinicopathologic features of gastrointestinal stromal tumors. A population-based study.

BACKGROUND: Although the diagnostic criteria and pathogenesis of gastrointestinal stromal tumors (GIST) have recently been elucidated, knowledge of the epidemiology of this malignancy is still limited. This study examined the incidence of GIST in the province of Modena, including pathologic features and clinical outcome. METHODS: Gastrointestinal mesenchymal tumors identified by the Modena Cancer Registry between 1991 and 2004 were analyzed with an immunohistochemical panel that included staining for CD-117 and PDGFRalpha. Size, mitotic rate, and other pathologic parameters were recorded. Each tumor was categorized into National Institutes of Health risk categories (very low, low, intermediate, and high risk). RESULTS: One hundred twenty-four cases were classified as GIST. The age-adjusted incidence rate was 6.6 per million. Seventy-five percent of patients were symptomatic; 34% had a previous or concomitant history of cancer. High-risk features were present in 47% of cases. Seventy-eight percent were submitted to radical surgery. After complete resection, the 5-year disease-free survival rates were 94%, 92%, 100%, and 40% for patients at very low, low, intermediate, and high risk, respectively. In multivariate analysis, high risk was the main predictor of recurrence. CONCLUSION: This population-based study shows that the incidence of GIST in Northern Italy is comparable to that reported in other European countries. Survival was favorable in lower risk categories and in most of the resected cases. In our study, resected patients at very low, low, and intermediate risk had a similar outcome. Our data support the need to consider high-risk patients after complete surgical resection for treatment with the best available approach

All-oral metronomic DEVEC schedule in elderly patients with peripheral T cell lymphoma

Purpose: Peripheral T cell lymphomas (PTCLs) have an overall poor prognosis. Indeed, registry data in elderly patients show that the median progression-free survival (mPFS) following first- and second-line therapies are only 6.7 and 3.1 months, respectively. The aim of the study is to show the activity of metronomic chemotherapy, a regular administration of low chemotherapeutic drug doses allowing a favourable toxicity profile, on elderly PTCL patients. Methods: We report a series of 17 PTCL patients, treated with the all-oral metronomic schedule DEVEC (prednisolone–etoposide–vinorelbine–cyclophosphamide) in four Italian centres. Patients 5/17 (29.4%) were treatment-naïve (naïve) and 12/17 (70.6%) were relapsed-refractory (RR), respectively. The median age was 83 years (range 71–87) and 71.5 years (range 56–85) for naïve and RR, respectively. In vitro activity of metronomic vinorelbine (VNR), etoposide (ETO) and their concomitant combination on HH, a PTCL cell line, was also assessed. Results: Histology: PTCL-not-otherwise-specified = 12; angioimmunoblastic = 2; NK/T nasal type = 1; adult-type leukaemia lymphoma = 1, transformed Mycosis Fungoides = 1. The overall response rate was 80 and 58% in naïve and RR, respectively; whereas the PFS was 20 in naïve (95% CI 0–43) and 11 months (95% CI 4.2–17.8) in RR. The occurrence of relevant adverse events was 23.5%, which was managed with ETO dose reduction. In vitro experiments showed that both metronomic VNR and ETO caused a significant inhibitory activity on HH cells and a strong synergism when administered concomitantly. Conclusion: All-oral DEVEC showed an encouraging activity and acceptable toxicity. This schedule deserves further studies in elderly PTCL also for assessing combinations with targeted drugs

Toxic metal enrichment and boating intensity: sediment records of antifoulant copper in shallow lakes of eastern England

Tributyltin (TBT), an aqueous biocide derived from antifouling paint pollution, is known to have impacted coastal marine ecosystems, and has been reported in the sediment of the Norfolk and Suffolk Broads, a network of rivers and shallow lakes in eastern England. In the marine environment, the 1987 TBT ban has resulted in expanded use of alternative biocides, raising the question of whether these products too have impacted the Broads ecosystem and freshwaters in general. Here we examine the lake sediment record in the Norfolk and Suffolk Broads for contamination by copper (Cu) (as an active biocide agent) and zinc (Zn) (as a component of booster biocides), to assess their occurrence and potential for causing environmental harm in freshwater ecosystems. We find that, after the introduction of leisure boating, there is a statistically significant difference in Cu enrichment between heavily and lightly boated sites, while no such difference exists prior to this time. At the heavily boated sites the onset of Cu enrichment coincides with a period of rapid increase in leisure boating. Such enrichment is maintained to the present day, with some evidence of continued increase. We conclude that Cu-based antifouling has measurably contaminated lakes exposed to boating, at concentrations high enough to cause ecological harm. Similar findings can be expected at other boated freshwater ecosystems elsewhere in the world

The classic prognostic factors in advanced Hodgkin\u2019s lymphoma patients are losing their meaning at the time of Pet-guided treatments

The International Prognostic Score (IPS) is the most commonly used risk stratification tool for patients with advanced Hodgkin lymphoma (HL). It incorporates seven clinical parameters independently associated with a poorer outcome: male sex, age, stage IV, hemoglobin level, white blood cell and lymphocyte counts, and albumin level. Since the development of the IPS, there have been significant advances in therapy and supportive care. Recent studies suggest that the IPS is less discriminating due to improved outcomes with ABVD therapy. The aim of the present study was to asses if classic prognostic factors maintain their prognostic meaning at the time of response-adapted treatment based on interim PET scans. We evaluated the prognostic significance of IPS in the 520 advanced stage HL patients enrolled in the PET-guided, HD0801 trial in which PET2-positive patients underwent a more intense treatment with an early stem-cell transplantation after 2 cycles of ABVD. We observed that in these patients, the IPS completely loses its prognostic value together with all the single parameters that contribute to the IPS. Furthermore, neutrophils, monocytes, lymphocytes, and the ratio among them also no longer had any predictive value. We believe that the substantial improvement in survival outcomes in PET2-positive patients treated with early autologous transplantation could explain the complete disappearance of the residual prognostic significance of the IPS