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Diamond foils are exceptionally strong yet brittle. One approach to make ceramic foils less susceptible to brittle fracture is to introduce interfaces into the material that provide pathways for crack deflection. In this study, we were able to produce strong yet tough diamond/metal laminates (DMLs) from freestanding diamond foils using a brazing process. The mechanical behavior was characterized via three-point bending (3PB) where the laminates exhibit step-like fracture. Crack deflection at interfaces induces toughening within the laminates. At approx. 3.0 MJ/m3 diamond/metal laminates exhibit more than twice the fracture energy of monolithic diamond foils while maintaining 90 % stiffness and about 70 % nominal strength. Classical laminate theory (CLT) supports the assessment of the deformation behavior and step-like fracture of diamond/metal laminates. We find that the diamond-to-metal interface plays a critical role: it must be strong enough to enable the transfer of shear stress, while being weak enough to deflect a crack.

Purpose The main purpose of this study was to determine whether there is a correlation between the change of tibial tuberosity-trochlear groove (TT-TG) distance and clinical outcomes after total knee arthroplasty (TKA). Methods A total of 52 knees undergoing TKA due to primary osteoarthritis were included in this retrospective study. All patients had pre- and postoperative CT scans. TT-TG distance was measured by two independent observers and the following alignment parameters were measured: hip-knee ankle angle (HKA), femoral mechanical angle (FMA), tibial mechanical angle (TMA), and posterior condylar angle (PCA). Clinical outcome was assessed using Knee Society Score (KSS) pre- and post-operatively and at a minimum of 12-month follow-up. Evidence of AKP was noted from follow-up reports. Pre- and postoperative scores were compared using a paired Student t-test. Pearson correlations were calculated to assess the influence of TT-TG on clinical outcome and of alignment parameters on the change in TT-TG. TT-TG between patients with and without AKP was compared using unpaired Student’s t-test (p Results Neither the absolute postoperative TT-TG nor the amount of change in TT-TG correlated with the post-operative KSS or the change in KSS. Post-operative TT-TG and change in TT-TG did not differ significantly between patients with and patients without AKP. Only the change in FMA showed a correlation with the change in TT-TG (p = 0.01, r = 0.36). Conclusion Despite a missing correlation between outcomes and TT-TG distance in this study, excessive TT-TG distance should be avoided. Furthermore, surgeons need to be aware that changes in femoral joint line orientation might affect TT-TG distance.

In the present work, we investigate the efficiency of TiO2 photoelectrode layers on boron doped diamond foil (BDDF) in comparison with a classic conducting glass (FTO) back contact. Crystalline thin TiO2 layers were prepared on the substrates by two different methods: (i) deposition of metallic Ti thin films followed by thermal oxidation to form TiO2 (TO-TiO2), (ii) reactive sputter deposition of TiO2 thin films and crystallization of these layers (SP-TiO2). Optimized layers show that TO-TiO2 films on BDDF deliver a significantly higher incident photon to current efficiency (IPCE) compared to directly sputtered SP-TiO2 layers and these layers on BDDF also outperform conducting glass (FTO) as a back contact. We ascribe this beneficial effect of the BDDF back contact to the formation of an intermediate conductive phase of Ti-carbides at the TO-TiO2/BDDF interface.

Here we report a novel structuring technique for diamond coatings using a copper masking on a previously deposited diamond layer to epitaxially grow a subsequent diamond layer only at the exposed areas of the mask. An 8 μm thick copper mask is applied onto the substrate using physical vapor deposition and structured by standard photolithographic methods. Hot filament chemical vapor deposition is used to grow the 14 μm thick structured diamond layer on the diamond coated silicon wafer. Micro and nano crystallinity of the diamond layers are varied, as well as the doping with boron to verify the applicability of the new structuring method for different kinds of diamond qualities. It is shown that four-inch wafers can be fully structured with this high temperature masking technique and the resolution was mostly affected by the quality of the printed mask used for the photolithographic structuring of the copper mask. This diamond structuring method could pave the way for diamond being used in electronics or adding additional functionalities to diamond coated tools.