Characterization And Preparation Of Ruthenium Boride Performance

Transition metal borides possess the two design parameters for the selection ofsuperhard compounds, i.e., a high valence electron density and the presence of directionalshort covalent bonds, which makes them the most promising new hard and superhardmaterials to substitute the conventional diamond and cubic boron nitride. The transitionmetal borides which have the possibility to be superhard have attracted increasing attention.Very recently, researchers have done a lot of work on the transition metal (especially thePlatinum group metal) borides materials, but there are still problems such as thepreparation process is relatively complex and high cost. Therefore, a relatively simplepreparation method remains to be developed.In the present paper, we focus on the compounds of Ru–B system. The Ru–B bulksand films were prepared by the Spark Plasma Sintering (SPS) and magnetron sputteringtechniques respectively. The preparation technics were investigated. The phase,microstructure and properties of samples were researched and analyzed by use of XRD,SEM, TEM and XPS techniques.In the present paper, the pure RuB bulks without second phase were prepared by theSPS technique successfully. The RuB samples are well-crystallized. The technologicalparameters of preparing the RuB bulks is: the pressure:35MPa, the heating rate:40℃/min,the sintering temperature:1300~1400℃, the holding time:5min. There were three stagesin the SPS process of preparing single-phase RuB bulks, which are primary stage,intermediate stage and terminal stage. The intermediate stage which ranges from750℃to1190℃approximately is the main stage that the Ru reacts with B element. Thesingle-phase RuB2bulks were not prepared by the SPS technique successfully, and there isa little Ru2B3phase in the samples.The holes in RuB samples decrease and the density increases with the increase ofsintering temperature. The highest relative density is93.34%and the Vickers hardness reaches9.7GPa. There is a gap in the mechanical properties of RuB bulks when comparedwith other literatures. The holes in RuB2samples are significantly reduced and its densityis improved compared with RuB samples. The Vickers hardness of RuB2samples goes upto12.3GPa. Considering the above results in phases and Vickers hardness, we can inferthat the hardness of Ruthenium borides increases with the increase of B element content.The Ru-B films with good quality in surface were prepared by magnetron sputteringtechnique successfully. The Ru-B films deposited at room temperature are all amorphous.There exist Ru-B bonds in both target and films. The deposition rate is not changed withthe sputtering time, but increase linearly with the sputtering power. The surface of Ru-Bfilms are made of small circular particles and the surface is uniform, dense and finewithout obvious defects such as cracks or voids. The surface roughness is under3nm. Thesurface grain size and roughness increase with the sputtering time. The influence on thefilm surface morphology of sputtering power can be explained by the nucleation growthand the migration diffusion rate of substrate surface particles. The sputtering power affectsboth the nucleation growth and the migration diffusion rate, and then affects the surfacemorphology.This research shows that, the SPS technique can reduce the sinter temperature,simplify the sintering process and improve the efficiency of sintering when preparing Ru-Bbulks. So, the SPS technique is a effective method to prepare Ru-B bulks by reactionsintering, the preparation of Platinum group metal borides bulks using SPS is feasible. Themagnetron sputtering technique provides a new approach and new idea in preparing thePlatinum group metal borides films. Therefore, the research of two techniques above hasgreat significance.