Optimized sintering and mechanical properties of Y-TZP ceramics for dental restorations by adding lithium disilicate glass ceramics

The novel dental ceramics can be fabricated at lower temperatures when sol-gel derived lithium disilicate glass ceramics(LDGC)was used as an additive for yttria stabilized tetragonal zirconia polycrystalline(Y-TZP)ceramics.The effect of LDGC on the sintering,mechanical,and translucent properties of Y-TZP ceramics was investigated in the present study.The results showed that the LDGC additive effectively improved the densification of Y-TZP at 1100℃,which was much lower than the sintering temperature for pure Y-TZP.When sintered at 1100℃,the Y-TZP with 1 wt%LDGC reached a relative density of 95.45%,and prossessed a flexural strength of 482.4 MPa and a fracture toughness of 5.94 MPa-m12.Moreover,its translucency was also improved.While,the addition of LDGC could result in an escape of yttrium atoms from the grain lattice of zirconia,which induced the tetragonal-monoclinic transformation of zirconia and abnormal growth of monoclinic grains.The escaped yttrium atoms diffused into the intergranular glass phase.The results indicated that the novel Y-TZP-LDGC ceramics has a great potential to be used for all-ceramic restorations.

Transition metal on topological chiral semimetal PdGa with tailored hydrogen adsorption and reduction

The difficulties in designing high-performance hydrogen evolution reaction(HER)catalysts lie in the manipulation of adsorption behaviors of transition metals(TMs).Topological chiral semimetals with super-long Fermi arc surface states provide an ideal platform for engineering the catalytic performance of TMs through the metal-support interaction.We found the adsorption trends of TMs can be modified significantly when deposited at the surface of the PdGa chiral crystal.The electron transfer from the TMs to the surface states of the PdGa reshapes the d band structure of TMs and weakens the hydrogen intermediate bonding.Especially,W/PdGa is expected to be a good HER catalyst with close to zero Gibbs free energy.Experimentally,we found a Pt-like exchange current density and tumover frequency when depositing W atoms at the PdGa nanostructures surface.The findings provide a way to develop high-efficient electrocatalysts by the interplay between topological surface states and metal-support interaction.