Effect of ZrO_2 Content on the Properties of Diamond Grinding Wheel Vitrified Bond

The effect of ZrO2 content on the performance of vitrified bond was discussed. The results showed that when the ZrO2 content was less than 2 mol%, Zr4＋ could enter into the glassy network as mending nets and agglomeration composition. In this case, with the increasing of ZrO2, the vitrified bond＇s bending strength increased and the expansion coefficient decreased. It was also found that the wetting angle between the vitrified bond and diamond got small because Zr4＋ was enriched on diamond surface. When ZrO2 content was more than 2 mol%, a part of ZrO2 existing in vitrified bond as ZrO2 particles played the role in nucleating agents and promoting the separation of spodttrnene. When ZrO2 content was 3 mol%, the bending strength of the vitrified bond reached its maximum of 128 MPa and the wetting angle with the diamond reached its minimum of 37.6°.

The effects of temperature and acid number of crude oil on the wettability of acid volcanic reservoir rock from the Hailar Oilfi eld

Wettability of acid volcanic reservoir rock from the Hailar Oilfield, China, was studied with crude oils of different acid numbers generated from an original crude oil with an acid number of 3.05 mg KOH/g. The modifed oils and their resultant acid numbers were： A （2.09 mg KOH/g）, B （0.75 mg KOH/g）, C （0.47 mg KOH/g）, D （0.30 mg KOH/g）, and E （0.18 mg KOH/g）. Contact angles and improved Amott water indexes were measured to study the effects of temperature and acid number on the wettability of the acid volcanic reservoir rock. Experimental results indicated that the wettability was not sensitive to variation in temperature when using the same oil, but the acid number of the crude oil was a key factor in changing the wettability of the rock. The Amott water index, Iw was an exponential function of the acid number, and the Amott water index increased as the acid number decreased （i.e. Amott water index exponentially decreased with the acid number increase）. The Iw value of the core saturated with oil A, with an acid number of 2.09 mg KOH/g, ranged from 0.06 to 0.11, which indicated low water wetness. If the acid number of the oil decreased to 0.18 mg KOH/g, the Iw value increased to 0.95, which indicated strong water wetness. The contact angle decreased from 80~ to 35~ when the aid number decreased from 0.75 to 0.18 mg KOH/g, indicating a change towards more water wet conditions. The oil recovery by spontaneous imbibition of water also increased as the acid number of the oil decreased. As an example, at 80 ~C, the recovery of Oil A with an acid number of 2.09 mg KOH/g was only 7.6%, while Oil E with an acid number of 0.18 mg KOH/g produced 56.4%, i.e. an increase of 48.8%.

Effect of Matrix Modification on Durability of Cementitious Composites in an Acid Rain Environment

The durability of silane-modified mortar, a cementitious composite, in acid rain environment was investigated given its extensive usage as a structural material. The results indicated that the addition of silane decreased the compressive strength of the cementitious composite. Wetting angle was increased by incorporating silane into the matrix. Decrease in both water absorption ability and coefficient of capillary suction confirmed hydrophobicity as induced by silane addition. Results of mechanical testing, scanning electron microscopy and X-ray diffraction showed that the sulfuric acid resistance of mortar was enhanced by silane. Based on these results, it is revealed that silane addition inhibits the diffusion of water, and consequently, sulfate ion diffusion rate decreases, thereby resulting in reduction in the rate of corrosion of cementitious composites by sulfuric acid.

Design and Range of Application of Slot Bushings with Volumetric Orifice Fields

A design of a slot bushing with a volumetric field has been developed, which allows to produce continuous fibers from melts with difficult processing characteristics in order to produce fibers with better operating characteristics. The operability of the design was confirmed when solving two problems of special technological complexity. 1. 400 and 800 orifice bushings for production of continuous fibers from the basalt melt have been developed and recommended for manufacture. 2. The process of production of continuous fibers from standard glass using 2400 orifice bushing with perforated plates instead of orifice tips without air cooling, has been realized for the first time.

Analysis of Surface Wettability of Synthetic Magnetite

Relative contact angle and heat of wetting can be used to provide a measurement of surface wettability of synthetic magnetite. The comparison between synthetic and natural magnetite in terms of surface wettability showed that, using the same kind of wetting liquid, the difference in the relative contact angle was 10° between the concentrate and tailings obtained from reverse fl otation of synthetic magnetite, while the difference was more than 20° between the concentrate and tailings obtained from reverse fl otation of natural magnetite. As for the concentrate and tailings from reverse fl otation of synthetic magnetite with water as wetting liquid, the relative ratio of their wetting heat was 106.21%. In comparison, the relative ratio of wetting heat was 176.59% for concentrate and tailings from reverse fl otation of natural magnetite, showing a 70.38% difference.

AlN precipitation during steel solidification using CA model

Based on the principles of metal solidification and cellular automaton(CA),as well as AlN precipitation thermodynamics and kinetics,a CA model of interdendritic AlN precipitation was established by coupling a large-size mesh describing the dendrite growth of Fe-C-Al-N alloys and a small-size mesh representing AlN precipitation based on transient chemical equilibrium.The results of single dendrite growth stimulated by this model were compared with the Lipton-Glicksman-Kurz solution to verify the correctness of the matrix dendrite growth simulation.The AlN morphology and dimensions obtained from the CA model simulations are following the experimental results.The presence of equiaxed dendrite in the computational domain results in a significant coarsening of the columnar dendrite and a uniform solute distribution around them,and the AlN solid phase fraction decreases.Simulations of AlN precipitation at different wetting angles were also performed,and it was found that the solid phase fraction of AlN decreased with the increase in wetting angle.Thus,it is confirmed that the established model is an effective method to simulate interdendritic AlN precipitation.

Machine learning of metal-ceramic wettability

The adhesion and wetting between metal and ceramic is a basic problem in materials science and engineering.For example,past materials selection for metal-ceramic composites has relied on random trials and heuristics due to a limited understanding of their adhesion;the large chemical/structural variability that such interfaces can have hinders the identification of the governing factors.Here based on literature data,we have developed a database with~1,000 experimentally measured wetting angles at different temperatures and atmospheric conditions,and come up with a model for the wettability of ionocovalent ceramics(ICs)by metals using a machine learning(ML)algorithm.The random forest model uses the testing temperature and~40 features generated based on the chemical compositions of the metal and the ceramic as predictors and exhibits strong predictive power with an R^(2) of~0.86.Moreover,this model and the featurization code are integrated into a single computational pipeline to enable(1)predicting metal-IC wettability of interest and(2)high-throughput searching of ICs with the desired wettability by certain metals in the entire Inorganic Crystallographic Structure Database.As a demonstration of this pipeline,the wettability of a Li-ion and electron insulator(LEI),CaO,by molten Li is estimated and compared with ab initio molecular dynamics simulation result.This ML pipeline can serve as a practical tool for methodical design of materials in systems where certain metalceramic wettability is desired.

The influence of substrate and atmosphere on the properties of FeSiB(Cu,Nb) alloy melts

The surface tensions and contact angles of Fe_(78)Si_9B_(13) and Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 alloy melts were studied as a function of temperature in various atmospheres(vacuum, Ar and N_2 gas) and on different substrates(Si C, Al_2O_3 and BN). It is indicated that Si_3N_4, NbN, Fe_2 Al B and B_(13)C_2 are generated as new phases at the interface between the melt and substrate, and reactive wetting behaviour exists during the heating process. The surface tensions of two alloy melts on BN substrate both firstly decrease and then increase along with increasing temperature, leading to V-shaped surface tension versus temperature, which results from atomic diffusion effects in the surface layer during the oxidation of BN and formation of C-rich layer. Comparably, the surface tensions on Al_2O_3 and Si C substrates decrease with increasing temperature throughout the entire temperature range. Among three substrates, BN exhibits the mildest wetting behaviour. The vacuum environment has the strongest protective effect on melt stability among the tested atmospheres. These findings enrich our knowledge about the effects of the substrate and atmosphere on Fe-based alloy melts at a high temperature, and provide theoretical reference for designing jet nozzles in melt-spinning techniques.