Boron Nitride Superlattice Research Articles

Minimum thermal conductance in graphene and boron nitride superlattice

The minimum thermal conductance versus supercell size (ds) is revealed in graphene and boron nitride superlattice with ds far below the phonon mean free path. The minimum value is reached at a constant ratio of ds/L ≈ 5%, where L is the thickness of the superlattice; thus, the minimum point of ds depends on L. The phenomenon is attributed to the localization property and the number of confined modes in the superlattice. With the increase of ds, the localization of the confined mode is enhanced while the number of confined modes decreases, which directly results in the minimum thermal conductance.

Deposition and Tribology of Carbon and Boron Nitride Super Lattice Solid Lubricant Films

Carbon and boron nitride super lattice films were deposited by RF sputtering using two semicircular targets. Super lattice (C/BN)n films were deposited by control of the opposing time of substrate to each graphite and boron nitride semicircular targets respectively. Micro Vickers hardness, nanoindentation hardness and nanoscratch properties of these films were evaluated. Both micro Vickers and nanoindentation hardness of 4nm period (C/BN)n multi layered film are the highest of all period (C/BN)n films. The multi layered film with a proper period exhibits superior hardness and nanoscratch resistance. From the evaluation of nanoscratch test, oscillatory scratch test, and ball on disk tribo test, the friction coefficient of the 4-nm-period (C/BN)n multi layered film is lower than those of other period (C/BN)n, carbon, boron nitride and carbon nitride films. The 4-nm-period (C/BN)n multi layered films show the least damage and superior sliding endurance.

Deposition and Tribology of Carbon and Boron Nitride Superlattice Solid Lubricating Films.

Carbon and boron nitride superlattice films were deposited by RF sputtering using two semicircular targets. Superlattice (C/BN)n films were deposited by controlling the opposing time of the substrate to each of the graphite and boron nitride semicircular targets. Micro-Vickers hardness, nanoindentation hardness and nanoscratching properties of these films were evaluated. Both micro-Vickers and nanoindentation hardnesses of the 4nm-period (C/BN)n multilayered film are the highest of all (C/BN)n films. Multilayered film of a suitable period has superior hardness and nanoscratching resistance. From the nanoscratching test evaluation, oscillatory scratching test, and ball-on-disk tribo test, the friction of the 4nm-period (C/BN)n multilayered film is lower than those of other (G/BN)n, carbon, boron nitride and carbon nitride films. The 4nm-period (C/BN)n multilayered films show the least damage and superior sliding endurance.

Deposition and Microtrribology of Carbon Nitride and Boron Nitride Super Lattice Films.

Carbon nitride and boron nitride super lattice films were deposited by RF sputtering using two semicircular targets, and then Vickers, nanoindentation hardness and micro-wear resistance of these films were evaluated. (1) Super lattice films were deposited by control of the oppositing time of substrate to each graphite and boron nitride semicircular targets respectively. Super lattice layered structure was observed by TEM (Transmittance Electron Microscope). (2) The Vickers and nanoindentation hardness of the multi layered films change with layer period. The hardness of multi layered film with 4 nm period is the highest. (3) Micro wear properties of multi layered and mixed films are evaluated by using AFM. Wear resistance showed a similar tendency as a nanoindentation hardness results. The wear depth of multi layered film of 4 nm period is the lowest. Proper period multi layered film has superior microwear resistance. (4) The multi layered film composed of same thickness of CN and BN layers is higher than that of the layered film composed of different thick CN and BN multi layers. (5) Hardness and micro wear properties dependence on the order of multi layered film were evaluated. The super lattice film which has the CN top surface layer is higher hardness and wear resistant than those of the film which has the BN top surface.