However, there are two critical factors hindering its application: first, a high level of boron (about 66 at.%) leads to severe loss of material under the scouring of hot gas because of the rapid evaporation of boron oxides at temperatures above 1,200 °C (refs 9, 10), second, monolithic Zr B to form multi-phase ceramics.Here we design and fabricate a carbide (Zr) coating by reactive melt infiltration and pack cementation onto a C/C composite.It displays superior ablation resistance at temperatures from 2,000–3,000 °C, compared to existing ultra-high temperature ceramics (for example, a rate of material loss over 12 times better than conventional zirconium carbide at 2,500 °C).This is because the oxide layer expands and increases the weight countering any material loss from ablation, indicating an almost negligible loss of our carbide.This is over 12 times better than the loss of material for Zr C (assuming both carbides have the same volume expansion of oxides per second).The dots are the volume percentage of each phase calculated from each virtual slice. The zig-zag shape of the dot is due to the alternating plies. Figure 2 shows a photograph of the ablation test and the morphology of the tested sample.The grey area represents the top of the sample which has been excluded from quantification due to strong artefacts. Despite the low level of boron present, our carbide displayed the characteristic light green flame during the ablation test, which in contrast to the carbide (that is, Zr C. 2b,c, the ablated surfaces are relatively smooth and free from any obvious erosion hollows and cracks.
In general, a high MAR (that is, rapid loss of mass) and LAR (that is, rapid degradation of surface integrity) indicate poor ablation performance.
After six months of preparation, PUMC Pharmaceutical (PUMC) and NKF launched their first official joint project in China.
Working with a China Working Group of 10 key opinion leaders chaired by Dr. The key objective of the commentary program will be to implement KDIGO’s CKD-MBD guideline across China, with appointed NKF Ambassadors responsible for physician education and close monitoring of dialysis centers to measure and ensure continuous quality improvement (CQI). Danielle Green (Director of Global Activities, NKF), Dr. Wang Mei (Peking University People’s Hospital), and Dr. The afternoon workshop session was introduced by a discussion of CQI protocol.
Once the coating has been depleted, the carbon matrix would be exposed and be detached quickly by hot gas, causing a very high LAR (see the significance of change for LAR of the composites in Fig. However, the MAR change would be less because of the weight gains of oxides from the ceramics. (b) Comparison of surface of the 30 mm diameter samples before and after ablation.
Black-gray sample is before test, and middle and right samples experienced 120 s ablation of 2,000 °C and 2,500 °C, respectively.
Wang Haiyan (Peking University First Hospital), PUMC and NKF gathered with 44 of China’s leading nephrologists in Shanghai to launch the Chinese commentary on KDIGO’s CKD-MBD clinical guideline. The China Working Group then separated into groups defined by geographical region, and discussed with their constituents CQI implementation strategy for their local dialysis centers.