86results about How to "Eliminate microcracks" patented technology

The invention discloses a technological method for composite asynchronous polishing of ceramics using picosecond-nanosecond laser. The technological method comprises the steps of firstly, irradiatingthe ceramic surface to be machined through picosecond laser along a certain scanning trace, and removing micro protrusions of the ceramic surface, so that the preliminary flattening is achieved; meanwhile, generating a large number of micro-nano particles by using a removal mechanism for the electronic state of ceramic materials through picosecond laser, wherein the micro-nano particles exist at adjacent space areas of the irradiated ceramic surface; starting a low power nanosecond laser according to the preset time for tracing the scanning path of the picosecond laser, and irradiating and fusing the micro-nano particles uniformly distributed on the ceramic surface; and finally forming a compact and smooth fine-grain melted layer so that the polishing effect is achieved. According to the technological method, original pore cracks of the ceramic materials are repaired, and the shortcomings that a heat affected zone generated by traditional laser polishing is large and the material surface is liable to generate micro-cracks and pores are overcome; and low removal amount, high efficiency and accuracy and submicron-level fine polishing of the ceramic materials is achieved.

The invention discloses a high-air-tightness low-free-oxygen-content nano disperse copper alloy and a short-process preparation technology, and wherein the alloy components comprise Al2O3, Ca and La.The preparation technology is made by the following steps that preparing Cu-Al2O3 alloy powder by adopting an internal oxidation method, and then mixing the Cu-Al2O3 alloy powder with Cu-Ca-La alloy powder, wrap covering the mixed powder under the protection of argon, carrying out hot extrusion at 900-920 DEG C and then rotary forging, after rotary forging, the wrap covering is vacuumized to be less than or equal to 10<-3>Pa, the wrap covering is sealed and is placed in a nitrogen atmosphere with the temperature of 450-550 DEG Cand the pressure intensity of 40-60 Mpa for 3-5 hours. According to the preparation technology disclosed by the invention, the secondary solid reduction of Ca and La is utilized, so that residual free oxygen is effectively removed and the dispersion strengthening effect is achieved, and finally the high density is obtained through vacuum medium-temperature creep deformation. The disperse copper prepared by the invention has the advantages that low free oxygen content (<= 15ppm), high dimensional stability and good air tightness after hydrogen annealing, good in gas tightness, the gas leakage rate is less than or equal to 1.0*10<-10> Pa.m<3> / s, the preparation technology is suitable for industrial production and can be used as a variety of sealing device materials such as an electric vacuum shell sealing device and a novel energy automobile high-voltagedirect-current relay.

The invention described herein discloses a chemical mechanical machining and surface finishing process. A conversion coating is formed on the surface of a workpiece and is removed via relative motion with a tool, thereby exposing the workpiece to further reaction with the active chemistry. Low mechanical forces are used such that the plastic deformation, shear strength, tensile strength and / or thermal degradation temperature of the workpiece are not exceeded. Since the chemical mechanical machining and surface finishing process requires little force and / or speed of contact to remove the conversion coating, the equipment's mass, complexity and cost can be significantly reduced, while simultaneously increasing machining precision and accuracy. The present invention lends itself to a very controlled rate of metal removal, and can simply surface finish the workpiece, or if desired, can surface finish the workpiece simultaneously with the shaping and / or sizing process.