Number Of Pits Research Articles

Cavitation erosion behaviour of MAB-CU4 alloy: influences of cavitation number, attack angle, time, and stand-off distance

Abstract The present study comprehensively examines the cavitation erosion behaviour of a manganese aluminium bronze alloy (MAB-CU4 alloy) as a function of several parameters (i.e., cavitation angle, cavitation number, time, and stand-off distance), particularly focusing on the influences of cavitation angle on the surface morphology and topography of the alloy. According to the design of experiment (Taguchi experimental design) analysis, mass loss increased with cavitation number and attack angle, while increasing the stand-off distance resulted in a decrease in mass loss and an increase in the surface area affected by cavitation erosion. Cavitation erosion behaviour was most affected by the cavitation attack angle, with the cavitation attack angle contributing 69.1% to total erosion, according to variance analysis. At 90° cavitation attack angle, MAB-CU4’s erosion rate was 64% greater than that at 30°. Scanning electron microscopy and optical profilometry revealed that cavitation erosion damage at 90° occurred mostly in the grain interiors as cavitation pits due to severe plastic deformation and surface corrosion, whereas pit formation was restricted around the hard secondary phases at the grain boundaries. At 30°, deep cavitation pits were limited, the erosion crater expanded, and the number of pits was reduced. Overall, finer microstructures with more grain boundaries and secondary phases may improve cavitation erosion resistance at 90°. The present study is the first to comprehensively capture erosion damage at the microstructural scale and analyse the impact of microstructural features on the erosion damage during the cavitation erosion of MAB-CU4 alloy.

Pitting corrosion resistance of tempered N08825 alloy in the inner layer of bimetallic composite pipe

Pitting corrosion resistance of N08825 alloy in the inner layer of bimetallic composite pipe SA210A/N08825 tempered at 570∼720 ℃ was investigated in NH4Cl solution by scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical measurement techniques. The M23C6 precipitates, observed at the grain boundaries of inner layer alloy 825, exhibit a temperature-dependent behavior during tempering at 570∼720 ℃. The quantity of M23C6 precipitates and the pitting corrosion resistance change with the tempering temperature. When the tempering temperature increases from 570 to 660 ℃, the quantity of M23C6 precipitates increases, with the pitting potential (Ep) decreasing from about 499 ± 8.6 to 354 ± 6.7 mVSCE, the passive current density (ip) increases from about 1.9 ± 0.2 to 2.45 ± 0.3 μA cm-2, and the average number of pits on the specimen surface rises from 3 to 7. Conversely, when the tempering temperature increases from 660 to 720 ℃, the quantity of M23C6 precipitates decreases, leading to the Ep increases from about 354 ± 6.7 to 394 ± 14.6 mVSCE, the ip decreases from about 2.45 ± 0.3 to 2.34 ± 0.4 μA cm-2, and the average number of pits on the specimen surface decreases from 7 to 6. There is a strong relationship between the M23C6 precipitates and the pitting corrosion resistance. As the quantity of M23C6 precipitates increases, it results in the expansion of Cr-depleted zones on the specimen surface, the rise of passive film defects, and a subsequent reduction in the pitting corrosion resistance of inner layer alloy 825.

Orthosilicic acid inhibits human osteoclast differentiation and bone resorption.

Silicon (Si), which is present in the diet in the bioavailable form of orthosilicic acid (OSA) and is detected as a dissolution product of certain bone-substitute materials, is suggested to promote bone health, and enhance bone healing, respectively. Silicon has been shown to stimulate osteoblastic cell differentiation and function, although the effect of Si on human osteoclasts is unclear. The present study investigated the direct effects of Si on human osteoclast differentiation, gene expression, and bone resorption. Human CD14+ monocytes were isolated from buffy coats and cultured with M-CSF and RANKL in medium without or with Si (50 μg/ml; constituting 75% OSA). The effects of Si on osteoclast differentiation were evaluated by TRAP-staining and the expression levels of CtsK, CalcR, TRAP, and DC-STAMP measured by RT-qPCR. The effect of Si on the expression level of AQP9, which encodes a potential Si transporter, was also analyzed. Bone resorption was determined based on the number of resorption pits formed when the RANKL-stimulated monocytes were cultured on bone slices, and by the levels of type I collagen fragments released into the cell culture medium. Silicon significantly inhibited the number of TRAP+ multinucleated cells and the expression of osteoclast related genes but increased the late expression of AQP9. Furthermore, Si significantly inhibited the number of resorption pits and the amount of collagen fragments in the medium when cells were cultured on bone slices. Our results demonstrate that OSA inhibits RANKL-stimulated human osteoclast differentiation, gene expression of osteoclast phenotypic markers, and bone resorption.

Optimized substrate temperature for high-quality CdZnTe epitaxial film in X-ray flat panel detectors

Cadmium zinc telluride (CdZnTe or CZT) materials, favored for their physical superiority in optoelectronic applications, can be efficiently produced as large-area epitaxial film via close space sublimation (CSS), enhancing potential in flat-panel detector imaging. However, the application of CdZnTe epitaxial film in medical imaging equipment is limited by their lower resistivity, prolonged response times, and diminished sensitivity. By elevating the substrate temperature, we enhanced the number and depth of reverse sublimation pits on the surface of the CdZnTe epitaxial film, established an approximately 100 nm Zn-rich layer, broadened the bandwidth, and minimized electrode injection. Additionally, we observed an aggregation of dislocations at the edges of the reverse sublimation pits, which promoted surface recombination and reduced leakage current. These modifications significantly increased the film's resistivity to 1011 Ω cm. Further, they notably decreased the rise and drop times to 2 m s and 4 m s, respectively. Integrated with thin-film transistors (TFTs), the optimized CdZnTe epitaxial film now distinctly differentiate between air, plastics, and metals under X-ray examination. This improved performance of X-ray flat panel detectors (FPDs) based on CdZnTe epitaxial film is promising for the development of next-generation X-ray detection systems.

Lateral impact performance of pitting corroded CFST columns for offshore applications

This study investigates the lateral impact performance of circular concrete-filled steel tube (CFST) columns with pitting corrosion. A comprehensive set of 15 CFST specimens was meticulously constructed, including 3 non-corroded specimens used as controls and 12 specimens subjected to varying pitting corrosion conditions. These conditions included different depths, numbers of corrosion pits, and pitting corrosion distributions. Additionally, an extensive Finite Element Analysis (FEA) was conducted to gain detailed insights into the instantaneous dynamic responses of CFST columns with pitting corrosion under lateral impact. The FEA included failure mechanism investigation, stress and strain analyses, bending moment responses, strain rate changes, and energy transformations. The experimental and FEA results reveal that pitting corrosion significantly affects the dynamic behavior of CFST columns, demonstrating reductions in impact force and flexural capacity due to pitting corrosion, and highlighting the influence of corrosion depth, number of pits, and distribution on column behavior. Finally, a simplified model incorporating the effects of pitting corrosion was proposed to estimate the dynamic flexural strength of pitting corroded CFST columns. The results provide valuable insights for designing and assessing the structural integrity of CFST members in marine environments.

Model for random internalization of nanoparticles by cells

We propose a stochastic model for the internalization of nanoparticles by cells formulating cellular uptake as a compound Poisson process with a random probability of success. This is an alternative approach to the one presented by Rees [] who explained overdispersion in nanoparticle uptake and associated negative binomial distribution by considering a Poisson distribution for particle arrival and a gamma-distributed cell area. In our stochastic model, the formation of new pits is represented by the Poisson process, whereas the capturing process and the population heterogeneity are described by a random Bernoulli process with a beta-distributed probability of success. The random probability of success generates ensemble-averaged conditional transition probabilities that increase with the number of newly formed pits (self-reinforcement). As a result, an ensemble-averaged nanoparticle uptake can be represented as a Polya process. We derive an explicit formula for the distribution of the random number of pits containing nanoparticles. In the limit of the fast nucleation and low probability of nanoparticle capture, we find the negative binomial distribution. Published by the American Physical Society 2024

Investigation of Cretodorus (Hemiptera: Fulgoromorpha: Mimarachnidae) based on new adult and nymph fossils from mid-Cretaceous Myanmar amber

Here we report a new species, Cretodorus lijuanae sp. nov., of extinct Mimarachnidae from mid-Cretaceous amber of northern Myanmar. C. lijuanae sp. nov. was described based on one adult and three nymphal fossils. The new adult specimen exhibits the diagnostic features of Cretodorus and possesses a unique number and arrangement of sensory pits in the pronotum: nine sensory pits on one side, with five sensory pits between median and pronotal carinae and four sensory pits between lateral carina and margin, which is consistent in the nymphs. We also conduct morphometric analyses of forewings of all known species of Cretodorus, demonstrating that morphometrics are effectively discriminative for identifying Cretodorus fossils featuring few longitudinal veins and minimal differences in venation. Additionally, we report the nymphal fossils of Mimarachnidae for the first time. Three nymphal fossils, preserved in the same piece of amber alongside the adult specimen, exhibit the same nodule pattern on the thoracic notum in dorsal view, suggesting a feature linking adult and nymph of Mimarachnidae. These new specimens show morphological characteristics of the different developmental stages of C. lijuanae sp. nov., increasing the diversity of the Mimarachnidae in mid-Cretaceous amber from Myanmar. The preservation of three nymphs of the same age with an adult in the same piece of amber likely indicates aggregation behaviour in Mimarachnidae.

Effect of nitrogen on the electrical properties and growth mechanism of phosphorus-doped diamonds

De‑nitrogen-doped phosphorus and nitrogen‑phosphorus co-doped diamond single crystals were synthesized using the high pressure and high-temperature (HPHT) method at 6.0 GPa and 1450–1510 °C. The synthesis process was catalyzed using Fe80Ni20 as the catalyst of choice. The optical, mechanical, and electrical properties of the crystals were characterized. The effect of nitrogen atoms inside the diamond on a phosphorus-doped diamond was explored. The color of the diamond gradually became lighter with increasing Ti content, while the color of the crystal changed from yellow to dark green with increasing NaN3 content, and a large number of growth stripes and pits appeared on the surface. The infrared test showed that the addition of Ti reduced the concentration of nitrogen atoms inside the diamond, and the concentration of nitrogen atoms gradually increased with the addition of NaN3. Raman tests showed that the addition of Ti and NaN3 negatively affected the crystal quality. The X-ray photoelectron spectroscopy showed that phosphorus was successfully introduced into the diamond lattice in the form of CP and PO bonds under the conditions of nitrogen removal and nitrogen doping. Electrical tests showed that an n-type semiconducting diamond was successfully synthesized. However, the increase in nitrogen negatively affected the n-type conductivity.

Study on stability evaluation of goaf based on AHP and EWM—taking the northern new district of Liaoyuan city as an example

Throughout the history of coal mining in all countries of the world, large areas of goaf have been left behind, and sudden collapses and surface subsidence of large areas of goaf may occur, especially for mining areas with long mining cycles. The northern new district of the Liaoyuan mining area has been subjected to nearly half a century of mining activities, accompanied by a gradual accumulation of disasters, which have occurred frequently in recent years. In order to assess the stability of the goaf in the study area, this paper proposes a hybrid decision-making multi-factor integrated evaluation method. The distribution of underground goafs was determined using geophysical exploration techniques (seismic survey and transient electromagnetic method) and geological drilling exploration. First, an evaluation index system was established based on the specifications of the goaf, the ecological and geological environment, and the mining conditions; the system included 14 indicators. Two weight calculation methods, AHP-EWM, were employed to determine the comprehensive weight of each indicator by combining subjective and objective weights on the basis of improved game theory. Subsequently, the fuzzy comprehensive evaluation method was utilised to complete the stability rating of each block in the study area, and MapGIS and ArcGIS were employed to complete the drawing of the stability zoning map of the northern new district goaf. The study area was divided into three zones of stability, basic stability and instability, according to the critical value. These zones accounted for 23.03%, 36.45% and 40.52% of the total area of the study area, respectively. The comprehensive on-site investigation revealed a decrease in the size and number of collapse pits and the rate of damage to the houses from the unstable zone to the stable zone. This indicates that the results of the division are consistent with the actual situation. The classification results are consistent with the actual ground disaster situation, thus verifying the rationality and validity of the evaluation method. The results indicate that the stability of the study area is generally at the lower middle level.

Corrosion performance of naval brass in a simulated ocean water environment under different aqueous conditions

This study assesses the corrosion response of naval brass (NB) (Cu-39.0Zn-1.0Sn-3.5Pb wt.%) with ocean water salt mixture added in distilled water (DW), tap water (TW), and 50%Tap water + 50%Rain water (TW + RW) conditions. The NB in DW exhibited reduced weight loss and corrosion rate compared to TW and TW + RW conditions, which was maximum in TW condition. The electrochemical corrosion rates increased to 168 h and declined at 336 h, with higher corrosion rates witnessed in TW and lowest in DW conditions. The corrosion rate after 168 h in TW was 32 % higher than in DW condition. The corrosion products on NB include cuprite, atacamite, brochantite, and simonkolleite, more prevalent in TW conditions. The dezincification was minimal in DW but increased in TW and TW + RW conditions, peaking in TW condition. Pit number and size were smaller in DW but larger in TW and TW + RW conditions, with TW exhibiting the most extensive and deeper pits, indicating heightened corrosion from localized Zn dissolution. Zn removal from α and β′ phases was lower initially in DW while escalating in TW and TW + RW conditions over time. The NB in the TW condition showed prominent Zn removal than in DW condition, especially after 336 h.

Effects of ultrasonic impact on surface characterization of S355 steel welded joint

The effects of ultrasonic impact treatment (UIT) on the residual stress, the microhardness, the nano-hardness, the microstructure, the electrochemical corrosion resistance, the corrosion morphology, and the chemical composition of the S355 steel welded joints were investigated. In addition, the mechanism of improving the electrochemical performance of the S355 steel welded joints by the UIT was studied. The results showed that the UIT could significantly improve the electrochemical corrosion resistance of the S355 steel welded joints. The corrosion potential and impedance were increased, and the corrosion current density was decreased with the increasing of the UIT time. According to the corrosion morphology, it was observed that after the UIT, the number of corrosion pits in the welds and heat-affected zones of S355 steel welded joints significantly decreased, along with reductions in the depth and size of the pits. After the UIT, the grain size of the S355 steel welded joints was refined, and both the microhardness and the nano-hardness of the welded joint were increased, which indicated that substantial plastic deformation occurred on the S355 steel welded joint. Moreover, the UIT could significantly reduce and transform residual tensile stress into residual compressive stress in areas adjacent to the welds, and the residual compressive stress could be increased with the increasing of the UIT time. It can be concluded that the introduced compressive residual stress, the grain refinement, and the generated plastic deformation were the main factors in improving the electrochemical corrosion resistance.

Influence of temperature on hot corrosion behavior of GH4169 superalloy subjected to Na2SO4–NaCl salts attack

This work studies the hot corrosion behavior of GH4169 Ni-based superalloy, deposited with a mixture of salts comprising 95 wt% Na2SO4 and 5 wt% NaCl, across three distinct temperatures (i.e., 650 °C, 800 °C and 950 °C). Corrosion and non-corrosive exposure experiments were compared, yielding data on mass loss and gain, respectively. Material characterization results revealed that the corrosion layer was mainly comprised of Cr2O3, Fe2O3, NiO, Al2O3, TiO2, NbS2 and MoS2. Notably, as the temperature ascended from 650 °C to over 800 °C, the corrosion mechanisms underwent a transition from pitting to uniform corrosion, corresponding to low-temperature hot corrosion and high-temperature hot corrosion, respectively. At 650 °C, a large number of semi-ellipsoidal corrosion pits manifested on the surface. Conversely, at 800 °C and 950 °C, the corrosion layer on the surface exhibited nearly uniform spallation. The pit growth model and spallation dynamics model were, respectively, developed based on the observed microstructure features. The models serve as tools for quantitative examination of the hot corrosion process of the superalloy at different temperatures.

Influences of (Al, Ca, Si, Nb, Mn)-oxy-sulfide inclusions on corrosion degradation for newly designed 17–4 martensitic PH steel in simulated geothermal environments

Influences of (Al, Ca, Si, Nb, Mn)-oxy-sulfide inclusions on hydrogen trapping and stress corrosion cracking in a newly designed 17–4 martensitic PH steel were carried out under simulated geothermal environments based on experiments and calculations. The results indicate that CaS and MnS in inclusions are not only prone to preferential dissolution, but also more likely to become hydrogen trapping sites at the interface with matrix than other components. The number of pits rapidly increase before the sample fracture at 159.25 h, while cracks around external pits and internal gourd-like cavities are probably attributed to the uneven expansion of inclusion-triggered pits.

Research on Friction Performance of Friction Stir Welding Tools Based on Non-Smooth Structure.

In this study, based on the principles of bionics, we fabricated a bionic non-smooth concave pit structure on the shoulders of friction stir welding tools and detected the thermal cycling curve, downforce, and torque of the tool in the welding process. We tested the wear loss weight and analyzed the surface morphology of the shoulder surfaces after welding for 200 m. This study found that as the distance between the concave pits decreased and the number of concave pits increased, the maximum downforce, torque, and temperature in the welding process showed a decreasing trend. As the speed increased, no matter how the tool structure changed, the downforce and torque decreased, while the peak thermal cycle temperature increased. The experimental welding results show that the wear loss weight of the non-smooth structure tool significantly reduced. The lowest wear loss weight of the tool with a concave pit interval of 1.125 mm was only 0.1529 g, which is 27% lower than that of the conventional tool. Our observations of the surface morphology of the tool shoulder after welding showed that the amount of aluminum swarf on the tool shoulder of the welding tool gradually declined with the increasing density of the uneven pits. The lowest number of aluminum chips adhered to a welding tool with a pit distance of 1.125 mm. Therefore, friction stir welding tools with biomimetic structures have better wear resistance and adhesion resistance.

Mechanical site preparation in South Africa: comparing the productivity of pitting machine operators under different site conditions

ABSTRACT Pitting is the preparation of a tree planting position. In South Africa, various contractors and grower companies have gradually adopted pitting machines over the past decade, to overcome the challenges of manual pitting, such as low productivity, poor ergonomics, and inconsistent pit quality. Even though most forestry stakeholders understand productivity requirements (e.g. pits/shift) from pitting machines, they are often unaware of productivity differences associated with different operators and work conditions. This study aimed to compare the operational productivity and pit quality achieved by different pitting machine operators under different site conditions. The experiment was conducted in two sub-compartments, with two different post-harvest slash treatments: broadcast burning or mulching (and pre-marking). Then, four operators were tasked to dig pits using the same equipment. Operator productivity was assessed by analyzing time study data, while pit quality was estimated by determining pit depth and diameter. The results indicated that Operator 4 performed significantly better on mulched sites (543 pits/PMH) than on burned sites (430 pits/PMH), while Operator 2 was the least productive with 261 and 253 pits/PMH in mulched and burned sites, respectively. The overall average productivity was 120 pits/PMH higher on mulched sites than on burned sites. Although work quality did not correlate with productivity, there were differences between operators on the mulched site. The proportion of good pits varied, but site preparation technique did not significantly affect pit quality. We conclude that operator experience significantly impacts productivity and that marking the pitting spots is important to ensure that the required number of pits per hectare is achieved.

Effect of Nitrogen on the Precipitation and Pitting Corrosion Susceptibility of High Nitrogen 316SS Weld

The present study aimed to understand the effect of nitrogen on the carbide precipitation and its influence on pitting corrosion of shielded metal arc welded high nitrogen 316SS weld. Nitrogen addition to weld reduces Cr availability sites in ferrite and enhances Cr in nearby austenite. Although higher carbon and continuous ferrite with ferritic austenitic mode exist, the changes in the degree of sensitisation were avoided at all the stages, and marginal changes in pitting potential (Epit) at 898 K/100 h and 998 K/24 h were observed. Nitrogen addition to weld further reduced the number of stable pits in ferrite and austenite, and the protectiveness of passive film was affected by nitrogen in ferrite and austenite, which affected pit propagation. This results in stable pits in ferrite and austenite, which affects pit propagation during thermal ageing.

New record of Cretaceous Protocircoporoxylon wood from the Guyang Basin, northern China and its palaeoclimatic implications

Abundant and diversified Mesozoic fossil wood records have been reported in China. However, fossil woods have never been reported in the Guyang Basin, northern China. Here, a new calcified fossil wood specimen was discovered from the Lower Cretaceous Guyang Formation in the Guyang Basin. The present fossil are characterized by araucarian radial tracheid pitting and circopore cross-field pitting, typical of the genus Protocircoporoxylon. The specimen described here are mostly distinguishable from other fossil species of Protocircoporoxylon by the araucarian radial tracheid pitting and the number of pits per cross-field. Therefore, the present wood fossil is established as a new species, Protocircoporoxylon guyangensis Xu X.H. et Zhao Y.M. sp. nov. Up to now, the fossil detail records of Protocircoporoxylon have predominantly been found in the Triassic and Jurassic periods thus far. However, this discovery in Inner Mongolia, northern China indicates that the genus Protocircoporoxylon still into the Early Cretaceous period. The quantitative growth rings analysis of P. guyangensis sp. nov. indicates that it is an evergreen gymnosperm with a leaf retention time of 5–7 years. The fossil wood living in an environment with complacent water supply and weak seasonal fluctuations.

Study on the screening of marine beneficial bacteria and the inhibition of sulfate-reducing bacteria corrosion in marine oil field produced water

PurposeThe purpose of this study is to provide ideas and theoretical guidance for green, environmentally friendly and efficient “bacteriostasis with bacteria” technology.Design/methodology/approachIn this paper, a beneficial strain of bacteria was extracted and purified from marine mud. Weight-loss test, morphological observation and electrochemical test were used to systematically study the effect of sulfate-reducing bacteria (SRB)-induced corrosion inhibition on X65 steel in simulated offshore oil field production water.FindingsThe results showed that a beneficial strain was selected and identified as Vibrio alginolyticus. Under the condition of co-culture of SRB, the average corrosion rate of X65 steel was significantly reduced. In the mixed bacterial system, the surface of X65 steel samples was relatively flat, and the structure of biofilm and corrosion product film was dense. The number of corrosion pits, the average diameter and depth of corrosion pits were significantly reduced. The localized corrosion of X65 steel was significantly inhibited.Originality/valueThe complex and changing marine environment makes the corrosion problem of marine steel increasingly severe, and the microbiologically influenced corrosion (MIC) caused by SRB is particularly serious. The research and development of environmentally friendly corrosion protection technology is a long-term and difficult problem. The use of beneficial microorganisms to control MIC is a green and efficient anticorrosion measure. Compared with terrestrial microorganisms, marine microorganisms can adapt to complex environments, and their metabolites exhibit special biological activities. The use of marine beneficial bacteria can inhibit SRB activity to achieve the corrosion inhibition effect.

A stochastic modeling method for three-dimensional corrosion pits of bridge cable wires and its application

ABSTRACT Cables have usually served as critical and vulnerable structural components in long span cable-supported bridges. Cable inspections revealed that corrosion, fatigue or coupled corrosion-fatigue were the ones of the main failure mechanisms. This paper proposed a stochastic modelling method for three-dimensional (3-D) corrosion pits of high-strength bridge wires, which can be applied to rapid fatigue life evaluation according to mass loss caused by surface corrosion pits of bridge wires nondestructively. High-strength steel wire specimens dismantled from the cable-stayed bridge served for 15 years were scanned to obtain the original surface corrosion data. The spatial position coordinate of corrosion pits were considered as random variable and can be well fitted by uniform distribution. While the number of corrosion pits can be fitted with generalized extreme value (GEV) distribution. The uniform corrosion depth du, which can be equivalent to mass loss rate, was calculated as the input corrosion parameter for 3-D corrosion pit modelling. The maximum pitting depth dmax for the steel wire was found to be associated with du. The geometric parameters for individual corrosion pits were recognized as pit depth d, depth-to-width ratio d/b, and aspect ratio b/a, which were fitted with different probability distributions. What follows is 3-D spatial corrosion pits simulation based on the individual corrosion parameter that were sampled and combined from the corresponding probabilistic distributions. Hereafter, fatigue life evaluation of corroded wires was conducted based on equivalent surface defect method and compared with the experimental results, verifying the effectiveness of the proposed modelling approaches.

Surface characteristics of precision as-cut NdFeB magnet considering diamond wire wear

NdFeB is the highest output value permanent magnet material at present, which has extremely high magnetic properties and is widely used. In the production process of NdFeB, cutting is an indispensable process, and high precision as-cut surface characteristics can reduce the cost of subsequent processes. In this paper, the single factor sawing experiment of NdFeB was carried out by using the range of processing parameters in industrial production. The effects of workpiece feed speed, saw wire speed, workpiece processing size and diamond saw wire wear on sawing surface morphology, surface material brittleness removal ratio, roughness and waviness were studied. The research shows that the surface characteristics of the workpiece sawed in the stable wear stage of the diamond saw wire are the best. In all service stages of the saw wire, reducing the feed speed and workpiece processing size, and increasing the wire speed will reduce the surface roughness and waviness, reduce the number and size of pits, and reduce the proportion of brittle removal areas. The research results provide an experimental reference for the optimization of diamond wire saw cutting parameters of NdFeB.