The magnetic properties of the recycled hydrogenation disproportionation desorption recombination (HDDR) Nd-Fe-B powder, doped with a low weight fraction of DyF3 nanoparticles, were investigated. ...Spark plasma sintering (SPS) was used to consolidate the recycled Nd-Fe-B powder blends containing 1, 2, and 5 wt.% of DyF3 grounded powder. Different post-SPS sintering thermal treatment conditions (600, 750, and 900 °C), for a varying amount of time, were studied in view of optimizing the magnetic properties and developing characteristic core-shell microstructure in the HDDR powder. As received, recycled HDDR powder has coercivity (HCi) of 830 kA/m, and as optimally as SPS magnets reach 1160 kA/m, after the thermal treatment. With only 1–2 wt.% blended DyF3, the HCi peaked to 1407 kA/m with the thermal treatment at 750 °C for 1 h. The obtained HCi values of the blend magnet is ~69.5% higher than the starting recycled HDDR powder and 17.5% higher than the SPS processed magnet annealed at 750 °C for 1 h. Prolonging the thermal treatment time to 6 h and temperature conditions above 900 °C was detrimental to the magnetic properties. About ~2 wt.% DyF3 dopant was suitable to develop a uniform core-shell microstructure in the HDDR Nd-Fe-B powder. The Nd-rich phase in the HDDR powder has a slightly different and fluorine rich composition i.e., Nd-O-F2 than in the one reported in sintered magnets (Nd-O-F). The composition of reaction zone-phases after the thermal treatment and Dy diffusion was DyF4, which is more abundant in 5 wt.% doped samples. Further doping above 2 wt.% DyF3 is ineffective in augmenting the coercivity of the recycled HDDR powder, due to the decomposition of the shell structure and formation of non-ferromagnetic rare earth-based complex intermetallic compounds. The DyF3 doping is a very effective single step route in a controlled coercivity improvement of the recycled HDDR Nd-Fe-B powder from the end of life magnetic products.
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•The finer grain size magnet showed reduced internal oxidation.•Grain size has most influence on oxidation under the surface parallel to the c-axis.•Under this surface, bands of Co/Cu rich ...precipitates appear to retard oxidation.•Perpendicular to this, composition may be more important than grain size.•Composition, orientation & microstructure need consideration to minimise oxidation.
This work has examined the influence of grain size in sintered Sm2(Co,Fe,Cu,Zr)17-type permanent magnets on the growth of an internal oxidation zone (IOZ). Two magnets of similar composition but with average grain sizes of 46 μm and 170 μm respectively, were exposed to temperatures of 500 °C in air for times up to 1000 h. Overall, the smaller grained magnet showed a reduced growth rate of the IOZ (∼39.01 μm2h−1) compared to the larger grained magnet (∼48.95 μm2h−1) and a smaller irredeemable loss in Br (3.11%) after 1000 h. However, growth rate of the IOZ is shown to depend on the growth direction, in respect to the crystallographic c-axis of the matrix phase. The smaller grain size was shown to be most effective at retarding the growth of IOZ under surfaces parallel to the c-axis. It is proposed therefore, that a smaller grained sintered magnet may be the microstructure of choice for use in demanding, high temperature applications, where a protective coating is not always a possibility, such as a high-performance electrical machine with a surface mount PM rotor. Orientation of the exposed face must also be considered to minimise the resultant magnetic induction loss caused by oxidation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The dependence of the magnetic properties on the particle size of recycled HDDR Nd–Fe–B powders was investigated, with the aim to assess the reprocessing potential of the end-of-life scrap magnets ...via spark plasma sintering (SPS). The as received recycled HDDR powder has coercivity (Hci) = 830 kA/m and particles in the range from 30 to 700 μm (average 220 μm). After burr milling, the average particle size is reduced to 120 μm and subsequently the Hci of fine (milled) powder was 595 kA/m. Spark plasma sintering was exploited to consolidate the nanograined HDDR powders and limit the abnormal grain coarsening. The optimal SPS-ing of coarse HDDR powder at 750 °C for 1 min produces fully dense magnets with Hci = 950 ± 100 kA/m which further increases to 1200 kA/m via thermal treatment at 750 °C for 15 min. The burr milled fine HDDR powder under similar SPS conditions and after thermal treatment results in Hci = 940 kA/m. The fine powder is further sieved down from 630 to less than 50 μm mesh size, to evaluate the possible reduction in Hci in relation to the particle size. The gain in oxygen content doubles for <50 μm sized particles as compared with coarser fractions (>200 μm). The XRD analysis for fractionated powder indicates an increase in Nd2O3 phase peaks in the finer (<100 μm) fractions. Similarly, the Hci reduces from 820 kA/m in the coarse particles (>200 μm) to 460 kA/m in the fine sized particles (<100 μm). SPS was done on each HDDR powder fraction under the optimal conditions to measure the variation in HCi and density. The Hci of SPS-ed coarse fraction (>200 μm) is higher than 930 kA/m and it falls abruptly to just 70 kA/m for the fine sized particles (<100 μm). The thermal treatment further improves the Hci to >1000 kA/m only up to 100 μm sized fractions with >90% sintered density. The full densification (>99%) is observed only in the coarse fractions. The loss of coercivity and lack of sinterability in the fine sized particles (<100 μm) are attributed to a very high oxygen content. This implies that during recycling, if good magnetic properties are to be maintained or even increase the HDDR powder particles can be sized down only up to ≥100 μm.
The primary recycling route – full recovery of magnetic properties possible in direct HDDR+SPS reprocessing. Coating removal pivotal, secondary recycling adds 4 times oxygen and particle size reduction degrades properties. Particle size reduction possible in: (1) Crushing; (2) HD; (3) HDDR routes (oxygen exposure should be controlled). The final particle size must be ≥100 μm to prevent excessive oxidation and retain magnetic properties. Display omitted
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The goal of this study was to justify the reprocessing of recycled HDDR Nd-Fe-B powders with spark plasma sintering (SPS) and to investigate the dependence of the final magnetic properties on SPS and ...thermal treatment. The initial recycled HDDR powder of the composition Nd13.4Dy0.6Fe78.6B6.1Nb0.4Al0.7 with 4760 ppm O2 content, coercivity (HCi) = 830 kA/m, and large particle size distribution <50–600 μm, was treated using the SPS parameters as follows: T = 650–850 °C for 1–5 min and 50 MPa pressure. The post SPS thermal treatment was performed at 750 °C for 15 min in vacuum. The optimal SPS conditions at 750 °C for 1 min, yielded fully dense magnets with the coercivity HCi = 1060 kA/m, which was boosted to 1160 kA/m after the post-SPS thermal treatment. The grain growth was obvious in samples SPS-ed above 800 °C and subsequently, the HCi was reduced. The SPS reprocessing beyond 850 °C was found to be detrimental to the overall magnetic properties due to the formation of bimodal grain size distribution origination from the abnormal grain growth (700–2600 nm). The redistribution of Nd-rich grain boundary phase between the Nd2Fe14B matrix grains in thermally treated magnets and the relaxation of the internal stresses induced via SPS are the possible reasons for the HCi surpassing the HCi of the starting recycled HDDR powder. It was shown that the SPS consolidation technique is suitable for producing fully dense nanograined bulk Nd-Fe-B magnets, with coercivities even exceeding the initial HDDR-powder and is one of the most suitable routes for revitalizing the Nd-Fe-B scrap magnets.
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•Scrap magnets are HDDR and SPS reprocessed to achieve high coercivity.•At 4760 ppm oxygen content, the recycled HDDR powder does not loose sinterability.•Coercivity of optimally SPS-ed HDDR powder equivalent to commercial HDDR powder.•Coercivity after SPS reprocessing is 30% higher than starting recycled HDDR powder.•Microstructure evolution detailed on SPS and thermally treated reprocessed powder.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The magnetic properties of the recycled hydrogenation disproportionation desorption recombination (HDDR) Nd-Fe-B powder, doped with a low weight fraction of DyF
nanoparticles, were investigated. ...Spark plasma sintering (SPS) was used to consolidate the recycled Nd-Fe-B powder blends containing 1, 2, and 5 wt.% of DyF
grounded powder. Different post-SPS sintering thermal treatment conditions (600, 750, and 900 °C), for a varying amount of time, were studied in view of optimizing the magnetic properties and developing characteristic core-shell microstructure in the HDDR powder. As received, recycled HDDR powder has coercivity (H
) of 830 kA/m, and as optimally as SPS magnets reach 1160 kA/m, after the thermal treatment. With only 1-2 wt.% blended DyF
, the H
peaked to 1407 kA/m with the thermal treatment at 750 °C for 1 h. The obtained H
values of the blend magnet is ~69.5% higher than the starting recycled HDDR powder and 17.5% higher than the SPS processed magnet annealed at 750 °C for 1 h. Prolonging the thermal treatment time to 6 h and temperature conditions above 900 °C was detrimental to the magnetic properties. About ~2 wt.% DyF
dopant was suitable to develop a uniform core-shell microstructure in the HDDR Nd-Fe-B powder. The Nd-rich phase in the HDDR powder has a slightly different and fluorine rich composition i.e., Nd-O-F
than in the one reported in sintered magnets (Nd-O-F). The composition of reaction zone-phases after the thermal treatment and Dy diffusion was DyF
, which is more abundant in 5 wt.% doped samples. Further doping above 2 wt.% DyF
is ineffective in augmenting the coercivity of the recycled HDDR powder, due to the decomposition of the shell structure and formation of non-ferromagnetic rare earth-based complex intermetallic compounds. The DyF
doping is a very effective single step route in a controlled coercivity improvement of the recycled HDDR Nd-Fe-B powder from the end of life magnetic products.
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In recent years rare earth metals have hit the headlines due to supply restrictions of neodymium and dysprosium from the main supplier China. The work in this thesis investigates the possibility of ...recycling sintered NdFeB-type magnets using a combination of hydrogen decrepitation (HD) and the HDDR process (Hydrogenation Disproportionation Desorption and Recombination). In this work the development of microstructure during the HDDR process has been identified and the route taken by hydrogen during absorption and desorption. The microstructure and magnetic properties have been shown to be affected by the process temperature, disproportionation pressure and recombination pressure and time. Sample batches up to 100g exhibit little variation in magnetic properties however 400g batches result in large variations partially due to incomplete recombination. By increasing the disproportionation pressure it was possible to simultaneously process mixed scrap feeds with different Dy and Co levels, however a large variation in magnetic properties was also observed. Optimal processing of sintered Nd\(_{13.4}\)Dy\(_{0.7}\)Fe\(_{78.6}\)Al\(_{0.7}\)Nb\(_{0.4}\)B\(_{6.3}\) was performed by in-situ HD followed by HDDR at 880\(o\)C with a disproportionation pressure of 1500mbar and recombination under vacuum. The resultant powder exhibited a remanence of 1.08 T, coercivity of 840 kAm\({-1}\) and maximum energy product of 178 kJm\({-3}\).
In recent years rare earth metals have hit the headlines due to supply restrictions of neodymium and dysprosium from the main supplier China. The work in this thesis investigates the possibility of ...recycling sintered NdFeB-type magnets using a combination of hydrogen decrepitation (HD) and the HDDR process (Hydrogenation Disproportionation Desorption and Recombination). In this work the development of microstructure during the HDDR process has been identified and the route taken by hydrogen during absorption and desorption. The microstructure and magnetic properties have been shown to be affected by the process temperature, disproportionation pressure and recombination pressure and time. Sample batches up to 100g exhibit little variation in magnetic properties however 400g batches result in large variations partially due to incomplete recombination. By increasing the disproportionation pressure it was possible to simultaneously process mixed scrap feeds with different Dy and Co levels, however a large variation in magnetic properties was also observed. Optimal processing of sintered Nd\(_{13.4}\)Dy\(_{0.7}\)Fe\(_{78.6}\)Al\(_{0.7}\)Nb\(_{0.4}\)B\(_{6.3}\) was performed by in-situ HD followed by HDDR at 880\(^o\)C with a disproportionation pressure of 1500mbar and recombination under vacuum. The resultant powder exhibited a remanence of 1.08 T, coercivity of 840 kAm\(^{-1}\) and maximum energy product of 178 kJm\(^{-3}\).
We examined the efficacy and safety of seladelpar, a selective peroxisome proliferator-activated receptor-delta agonist, in adults with primary biliary cholangitis (PBC) at risk of disease ...progression (alkaline phosphatase ALP ≥1.67xupper limit of normal ULN) who were receiving or intolerant to ursodeoxycholic acid.
In this 52-week, phase II, dose-ranging, open-label study, patients were randomized (1:1) to seladelpar 5 mg/day (n = 53) or 10 mg/day (n = 55) or assigned to 2 mg/day (n = 11; United Kingdom sites after interim analysis) for 12 weeks. Doses could then be uptitrated to 10 mg/day. The primary efficacy endpoint was ALP change from baseline to Week 8.
Mean baseline ALP was 300, 345, and 295 U/L in the 2 mg, 5 mg, and 10 mg cohorts, respectively. Twenty-one percent of patients had cirrhosis, 71% had pruritus. At Week 8, mean ± standard error ALP reductions from baseline were 26 ± 2.8%, 33 ± 2.6%, and 41 ± 1.8% in the 2 mg (n = 11), 5 mg (n = 49), and 10 mg (n = 52) cohorts (all p ≤0.005), respectively. Responses were maintained or improved at Week 52, after dose escalation in 91% and 80% of the 2 mg and 5 mg cohorts, respectively. At Week 52, composite response (ALP <1.67xULN, ≥15% ALP decrease, and normal total bilirubin) rates were 64%, 53%, and 67%, and ALP normalization rates were 9%, 13%, and 33% in the 2 mg, 5 mg, and 10 mg cohorts, respectively. Pruritus visual analog scale score was decreased in the 5 mg and 10 mg cohorts. There were no treatment-related serious adverse events, and 4 patients discontinued due to adverse events.
Seladelpar demonstrated robust, dose-dependent, clinically significant, and durable improvements in biochemical markers of cholestasis and inflammation in patients with PBC at risk of disease progression. Seladelpar appeared safe and well tolerated and was not associated with any increase in pruritus.
NCT02955602
2016-002996-91
Current treatment options for patients living with primary biliary cholangitis (PBC) are not optimal due to inadequate effectiveness or undesirable side effects. Patients with PBC who took seladelpar, a new treatment being developed for PBC, at increasing doses (2, 5, or 10 mg/day) for 1 year had clinically significant, dose-dependent improvements in key liver tests. Treatment appeared safe and was not associated with any worsening in patient self-reported itch scores.
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•Seladelpar (2, 5, 10 mg) was assessed in patients with primary biliary cholangitis.•ALP was dose-dependently reduced by 23% to 43% at Week 12.•ALP was normalized in 33% of patients in the 10 mg cohort at Week 52.•Up to 67% of patients met the composite ALP and bilirubin endpoint at Week 52.•Seladelpar was safe, with no treatment-related serious adverse events or deaths.
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Summary
Background
Seladelpar is a potent and selective peroxisome proliferator‐activated receptor‐δ agonist that targets multiple cell types involved in primary biliary cholangitis (PBC), leading to ...anti‐cholestatic, anti‐inflammatory and anti‐pruritic effects.
Aims
To evaluate the long‐term safety and efficacy of seladelpar in patients with PBC.
Methods
In an open‐label, international, long‐term extension study, patients with PBC completing seladelpar lead‐in studies continued treatment. Seladelpar was taken orally once daily at doses of 5 or 10 mg with dose adjustment permitted for safety or tolerability. The primary analysis was for safety and the secondary efficacy analysis examined biochemical markers of cholestasis and liver injury. The study was terminated early due to the unexpected histological findings in a concurrent study for non‐alcoholic steatohepatitis, which were subsequently found to predate treatment. Safety and efficacy data were analysed through 2 years.
Results
There were no serious treatment‐related adverse events observed among 106 patients treated with seladelpar for up to 2 years. There were four discontinuations for safety, one possibly related to seladelpar. Among 53 patients who completed 2 years of seladelpar, response rates increased from years 1 to 2 for the composite endpoint (alkaline phosphatase ALP <1.67 × ULN, ≥15% decrease in ALP, and total bilirubin ≤ULN) and ALP normalisation from 66% to 79% and from 26% to 42%, respectively. In those with elevated bilirubin at baseline, 43% achieved normalisation at year 2.
Conclusions
Seladelpar was safe, and markedly improved biochemical markers of cholestasis and liver injury in patients with PBC. These effects were maintained or improved throughout the second year. Clinicaltrials.gov: NCT03301506; Clinicaltrialsregister.eu: 2017‐003910‐16.
Seladelpar two‐year safety and efficacy results.
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10.
Featured Cover Mayo, Marlyn J.; Vierling, John M.; Bowlus, Christopher L. ...
Alimentary pharmacology & therapeutics,
January 2024, 2024-01-00, 20240101, Volume:
59, Issue:
2
Journal Article
Peer reviewed
Open access
The cover image is based on the Fast Track Open‐label, clinical trial extension: Two‐year safety and efficacy results of seladelpar in patients with primary biliary cholangitis by Marlyn J. Mayo et ...al., https://doi.org/10.1111/apt.17755
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