| Embedded thin film sensor has the advantages of high measurement accuracy and small sensor volume.At the same time,it can feed back the working conditions such as temperature and pressure on the surface of mechanical parts in real time.It has attracted much attention in the intelligent manufacturing industry.When facing the harsh environment of strong wear,it is a practical solution to embed the sensing function film under the hard wear-resistant protective film on the surface of the workpiece to prepare the structure function integrated film sensor.The sensor structure is composed of multi-layer films of metal matrix,insulation layer,sensing function layer,insulation layer and wear-resistant protective layer,in which the wear-resistant protective layer and insulating layer with good interface combination are very important to the service life of the sensor.In this thesis,the wear-resistant protective film and insulating film were prepared by physical vapor deposition technology.The effects of different process parameters on the structure and properties of the film were studied in order to improve the adhesion between the insulating layer and the wear-resistant protective layer and the metal matrix,and obtain the preparation method and process of high-quality wear-resistant protective layer and insulating layer.The main conclusions are as follows:(1)AlTiN wear-resistant protective films were prepared on insulating substrate by arc ion plating.The effects of substrate bias,transition layer thickness and ion etching process on the structure and properties of AlTiN films were studied.The prepared hard films were mainly composed of fcc-(Al,Ti)N phase structure.The adhesion and friction and wear properties of the films decreased under high substrate bias.Inserting appropriate thickness of Ti transition layer and increasing ion source etching current were beneficial to improve the adhesion of the film.When the substrate bias was-50 V(duty cycle of 60%),the Ti transition layer was deposited for30 min and the ion etching current was 110 A,the AlTiN film had the best bonding strength.(2)AlN insulating films were prepared by magnetron sputtering under different substrate bias conditions.The surface of AlN films were relatively smooth.The films contained hcp-AlN and fcc-Al phase structures.The insulation properties of AlN films increased first and then decreased with the increase of substrate bias.When the substrate bias was-400 V,the resistivity was the highest,but the adhesion between the film and metal substrate was poor.Vacuum annealing had a great influence on the resistivity of AlN films.Under high temperature annealing,the surface grain size of AlN films increased,the metal Al phase disappeard and the resistivity decreased gradually.(3)AlCrN and AlCrSiN films were prepared by arc ion plating and oxidized at high temperature.After high-temperature oxidation treatment,more large particles were formed on the surface of AlCrN and AlCrSiN films,the fcc-(Al,Cr)N structure in the films decomposed,and the oxide film formed on the film surface increased the resistance from kiloohm to megaohm.Among them,the insulation performance of AlCrSiN film was significantly improved,which is a new way to prdvide the preparation of high-temperature insulating film.(4)AlCrSiON insulating films with different oxygen content were prepared by arc ion plating.The insulating properties of the prepared nitrogen oxide films were equivalent to those of AlN films,and the resistance and resistivity increased with the increase of the thickness of oxygen-containing layer.When an appropriate amount of oxygen was added into AlCrSiN film,obvious oxide crystal phase appeard,and the crystallinity of the film decreased when the oxygen flow rate was too high.With the increase of oxygen flow,the surface particles of AlCrSiON film increased,the insulation performance increased,while the mechanical properties and friction and wear properties decreased,but maintained high bonding strength.In conclusion,the AlCrSiON film prepared under the condition of oxygen flow of 50 sccm has good comprehensive properties and is expected to be used as a wear-resistant insulating film in the field of thin film sensors. |
