9 research outputs found
Fireproofing of polyurethane elastomers by reactive organophosphonates
International audienc
New Phosphonated Methacrylates: Synthesis, Photocuring and Study of their Thermal and Flame-Retardant Properties
International audienc
Copper/carbon metal matrix composite fabricated by semi-liquid powder metallurgy process
Fabrication and characterization of MMC materials using an innovative solid-liquid co-existent phase process
Vieillissement hydrolytique de polyesters insatures reticules par le styrene
CNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc
Copper/carbon metal matrix composite fabricated by semi-liquid powder metallurgy process
Solid-liquid co-existent phase process: towards fully dense and thermally efficient Cu/C composite materials
Metal matrix composites are currently being investigated for thermal management applications. In the case of a copper/carbon (Cu/C) composite system, a particular issue is the lack of affinity between the Cu matrix and the C reinforcements. Titanium-alloyed Cu (Cu-Ti) powders were introduced in a Cu/C powder mixture and sintered under load at a temperature at which the Cu-Ti powders became liquid, while the rest of the Cu and C remained solid. Fully dense materials were obtained (porosity of less than 5%). The creation of regular and homogeneous interphases was confirmed. All Ti reacted with the carbon, hence purifying the Cu matrix. Thermal conductivities were enhanced as compared with the Cu/C composites without interphase. The chemical analyses are in agreement with thermodynamic simulations carried out to predict the phase transformation during the sintering process.Interactions and transfers at fluids and solids interface
Improved adhesion of polycrystalline diamond films on copper/carbon composite surfaces due to in situ formation of mechanical gripping sites
Diamond coatings are investigated for thermal management, wear protection and corrosion resistance in harsh environments. In power electronic industries, copper (Cu), which shows high thermal conductivity, is considered as a promising substrate for diamond based heat-spread materials. However, the coefficient of thermal expansion (CTE) mismatch between diamond and Cu induces thermo-mechanical stresses that affect the integrity of the diamond-Cu assembly. In fact, diamond films deposited on Cu substrates tend to peel-off upon cooling due to the compressive stresses present at the diamond-Cu interface. This investigation is focused on the growth of polycrystalline diamond thin films onto Cu/CF (CF) composite materials, using combustion flame chemical vapor deposition (CVD). It has been found that increased CF content in the Cu/CF materials leads to a reduced CTE improving, hence, the adhesion between the diamond film and the Cu/CF substrate and reduces Cu/CF-diamond interfacial residual thermal stresses. At a CF content of 40% in volume, the residual thermal stress of the diamond film deposited on the Cu/CF composite is lower than that on bare Cu and adapted with CVD diamond growth. Naturally engineered composite surfaces have enhanced the adhesion of the diamond film on the composite substrate via mechanical interlocking