Segregation Effects Research Articles

Interfacial Fe segregation and its influence on magnetic properties of CoFeB/MgFeO multilayers

Abstract We investigated effects of Fe segregation from partially Fe-substituted MgO (MgFeO) on the magnetic properties of CoFeB/MgFeO multilayers. X-ray photoelectron spectroscopy and magnetic measurements revealed that segregated Fe reduced to metallic Fe and ferromagnetism was exhibited at the CoFeB/MgFeO interface. The CoFeB/MgFeO multilayer showed a more than 2-fold enhancement in perpendicular magnetic anisotropy (PMA) energy density compared with that of a standard CoFeB/MgO multilayer. The PMA energy density was further enhanced by insertion of an ultrathin MgO layer between the CoFeB and MgFeO layers. Ferromagnetic resonance measurements also revealed a remarkable reduction of magnetic damping in the CoFeB/MgFeO multilayers.

190 Effect of Segregation in Pigs in the Nursery Period by Body Weight (Light, Medium, and Heavy) on the Productive Performance on Wean-to-Finish

Abstract A management strategy to improve growth performance at weaning is segregation of pigs in the nursery period by body weight (BW; Light, Medium, and Heavy) in an attempt to increase productive performance and decrease within pen variation in BW. However, the result of current studies indicated that this practice may not be as effective as not sorting pigs. The objective was to determine the effect on productive performance and coefficient of variation (CV) within four categories of BW: Normal (without segregation), Light, Medium, and Heavy. A total of 24 Experimental Units, (EU; 50% barrows and 50% gilts) in an Incomplete Randomized Block Design with four treatments (Trt) and six replicates per Trt. Pen was the EU and block was the weaning group. Treatments were four; Normal (without segregation; 6.35 kg BW); Light (4.45 kg BW); Medium (5.89 kg BW); and Heavy (7.15 kg BW). Pigs were weighed individually on d 21 (at the beginning of the experiment), 70, 119, 135 and 146 of life. Growth data were analyzed using PROC MEANS and GLM of SAS. Results indicated that at the beginning of the experiment (for design) BW and the CV were different (P < 0.05). From weaning to d 70 Medium and Normal categories had similar BW (29.79 vs. 30.57 kg; P > 0.05), respectively. Light and Heavy pigs remained unchanged in their weight categories. Interestingly, the CV at d 70 was 3.46 percentage points greater in all the groups of pigs that were regrouped by weight, in fact, the only group that reduced the CV at d 70 was the Normal (it was decreased by 3.26 percentage points). Average daily gain at day 70 was less (P < 0.05) for Light (0.62 kg/d) compared with any of the other treatments (0.69 kg/d, average of the rest of the treatments). Average daily feed intake was less for Light (0.940 kg/d) followed by Medium and Normal (1.00 and 1.04 kg per day, respectively) and the Heavy which had the greatest intake (1.08 kg/d). No differences were found in removed animals and mortality (P > 0.05). However, the total number of animals treated parenterally was greater in the Light and Medium (16.75 vs. 12.80, respectively; P < 0.05) than the Heavy and Normal (7.83 and 7.00, respectively, P < 0.05). At the end of the experiment the BW of the pigs was different between treatments (P < 0.05) being the Light group pigs the least heavy (120.62 kg), followed by the Medium (128.02 kg) and Normal (131.31 kg) the treatment Heavy was the heaviest with 133.04 kg. These results suggest that segregation in nursery by BW has a negative effect on the CV.

Effect of feed-size segregation on energy consumption during jigging: A CFD-DEM study

Segregation of feed based on size is used to increase the efficiency of gravity concentration by jig devices. Due to the variety of size and density of the particles in the feed, choosing how to segregate it before jigging is still a challenge. This article segregates the feed (with a size range of 3 to 8 mm) into the different states and then, simulates the jigging performance with the two-way coupling method of computational fluid dynamics and the discrete element method in 3 dimensions. In different states, the energy consumption and the number of cycles required for gravity concentration were compared, qualitatively. The simulation shows that the segregation of the jig feed into two size classes (3 to 4) and (5 to 8) mm decreases the energy consumption and the number of cycles. Therefore, the segregation state where the fine-grained part has a close size range and the coarse-grained part has a wide size range will have the lowest energy consumption and the number of cycles.

Numerical-simulation study on the influence of wind speed and segregation effect on spontaneous combustion of coal bunker

Coal bunker facilities are important places for coal storage and supply in coal-fired power generation, coal mines, ports, etc. Coal bunker spontaneous combustion(CBSC) disasters are mostly caused by the interaction of multiple field effects. In order to prevent and control coal bunker fires, it is necessary to study the impact of “chimney effect” wind speed and “segregation effect” on CBSC. This article establishes a two-dimensional geometric model based on the No.4 warehouse of Huanghua Port and the model is a two-dimensional representation of the longitudinal section along the warehouse axis. The research results indicate that at low temperatures in winter (273K), coal bunkers are less prone to spontaneous combustion; Under normal temperature (298K) and high temperature (308K) conditions, an increase in the initial wind speed in the vertical direction of the coal bunker inlet has a significant impact on the shortening of the CBSC period. The enhanced “segregation effect” of coal particles can shorten the spontaneous combustion period of coal bunkers and significantly affect the location of high-temperature zones. The research in this article has guiding significance for preventing and controlling coal bunker fires.

Unraveling the effects of Cr interface segregation on precipitation mechanism and mechanical properties of MC carbides in high carbon chromium bearing steels

This study explored the influence of Cr interfacial segregation on the precipitation mechanism and mechanical properties of MC carbides in high-carbon chromium bearing steels. The precipitation of Cr-doped MC carbides at different concentrations was investigated using microscopic morphological characterization (SEM, EDS and HR-TEM) alongside first principles calculations. The results indicated that both the austenite matrix and MC carbides exhibited, FCC structures, and the following orientation relationships of crystal planes in high-carbon chromium bearing steels were as follows: MC (010)//FCC-Fe (100) and MC (111)//FCC-Fe (111). Initially, Cr atoms adsorbed on the Fe-top site of the MC carbide (010) crystal plane, maintaining a distance of 2.5 Å from the Fe atom. Notably, when the Cr atom doping amount was 0.5, the Cr–Fe metallic bond exhibited a long bond length, large bond angle and low bond strength in the MC transition state (TS), resulting in a reduced, reaction barrier (908.08 kcal/mol), thus promoting the precipitation of MC carbide in bearing steel. However, at a Cr atom doping amount level of 1, the shorter bond length, small bond angle, and higher bonding strength of the Cr–Fe metallic bond in the MC TS, elevated the reaction barrier (49709.72 kcal/mol), inhibiting the precipitation of MC carbide in bearing steel. Additionally, this study quantitatively analyzed the effect of Cr atom content on the brittle plastic properties and hardness of MC carbides. At Cr atom contents of 0.23 and 1, the MC carbide hardness reached a minimum value of 3.0 GPa and a maximum value of 17.1 GPa, respectively. This investigation not only elucidated the atomic scale effects of Cr interfacial segregation on the precipitation mechanism and mechanical properties of MC carbides but also provided new ideas for controlling carbide precipitation in high-carbon chromium bearing steels.

Fabrication of bulk delta-phase Zirconium Hydride from Zircaloy-4 for use as moderators in microreactors

The fabrication of bulk delta-phase Zirconium Hydride (δ-ZrHx) using Zircaloy-4 as a precursor is herein reported. Characterization using electron-microscopy methods indicate that the fabricated material is of a single-phase. Sn-rich segregation zones have been observed to form as a direct result of the hydriding process. These findings experimentally validate previous ab initio calculations on the influence H incorporation in Zircaloy-4 constitutional elements such as Sn, Fe and Cr. The effect of hydriding and Sn segregation on pre-existing Zr(Fe,Cr)2 Laves phases is also evaluated. Major implications on the development of moderators for use in microreactors within the nuclear industry are discussed.

Do Moral Values Moderate the Relationship Between Immigrant-School Concentration and Violent Offending? A Cross-Level Interaction Analysis of Self-Reported Violence in Sweden

ABSTRACT The study examines whether school-level immigrant concentration is related to students’ involvement in violence, and whether students’ moral values moderate the relationship between immigrant concentration and violence. The study is based on six nationally representative school surveys conducted by the Swedish National Council for Crime Prevention between 1999 and 2011, with a combined sample of 38,711 adolescents. We have combined different surveys to create one large pooled data set to evaluate segregation effects at the school level. Multilevel linear probability models are used to examine cross-level interaction effects. This study shows that contextual effects impact students differently, and that the relationship between immigrant concentration and violence is considerably stronger for adolescents with weak personal moral values. The paper provides empirical support for the differential vulnerability hypothesis. Policy and practice would benefit from a focus on the further development of programs and interventions that target personal moral values, not least in schools.

The Effect of IMCs and Segregation on the Microstructure and Mechanical Properties of β-Type Titanium Alloys

Two new β-type titanium (β-Ti) alloys of Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al and Ti-15.6Cr-12Mn-3.3Zr were designed with the same bond order value 2.79 and different d-orbital energy level values of 2.28 and 2.16, respectively. The effect of intermetallic compounds (IMCs) and the segregation behaviors of β-Ti alloys were discussed by adding excessive and normal alloying elements to alloys under both as-cast and solution-treated conditions. The mono-β phase in the Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al alloy and β+intermetallic compounds (IMCs) in the Ti-15.6Cr-12Mn-3.3Zr alloy were identified and observed. The as-cast and solution-treated alloys showed their ultimate tensile strength and fracture strain; these were 982 and 1002 MPa, with 9.82 and 9.89% for Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al, and 448 and 296 MPa, with 0.12 and 0.11% for Ti-15.6Cr-12Mn-3.3Zr, respectively. Moreover, the Vickers hardness values of the as-cast and solution-treated alloys were 345 and 355 for Ti-10.5Cr-5.4Mn-2.4Zr-0.9Al, and 422 and 466 for Ti-15.6Cr-12Mn-3.3Zr, respectively.

Experimental study on the influence of grain boundary on breakdown in relativistic backward wave oscillator

The presence of radio frequency (RF) breakdown seriously degrades the performance of relativistic backward wave oscillator (RBWO) and affects its lifetime. In this paper, the influence of grain boundary on RF breakdown in an X-band RBWO has been experimentally investigated. Firstly, titanium with different grain sizes has been prepared using a high-temperature annealing method before its field emission characteristics are studied by a field emission test system. The experimental results indicate that the segregation effect of the impurities at the position of the grain boundary may become more pronounced as the grain size increases, which results in a significant improvement in the field emission performance of titanium. A high-power microwave experimental platform is then set up, and the influence of the grain boundary of titanium on RF breakdown has been revealed. The shortening of the microwave pulses is more serious with the increase of the grain size, and the corresponding breakdown traces appearing in the high-frequency structures become more apparent. Therefore, developing fine-grained and single-crystal metallic materials may be an important method for suppressing RF breakdown in RBWOs.

Spectroscopic determination of metal redox and segregation effects during CO and CO/NO oxidation over silica-supported Pd and PdCu catalysts

We report the effects of alloying Cu into silica supported Pd nanoparticles on the catalytic activity, surface composition, and particle structure during CO oxidation Pd is highly active for CO oxidation but is inhibited by relevant competitive reagents (e.g. NO) at low temperatures (< 150 °C). By alloying Cu into Pd nanoparticles, NO inhibition is suppressed without any CO oxidation activity loss. Infrared spectroscopy illustrates the formation of surface nitrosyl (NO-Pd) is eliminated in the PdCu alloy catalyst, preventing CO oxidation inhibition by NO. X-ray absorption spectroscopy studies show that Pd in the monometallic catalyst forms a surface oxide after light-off. Conversely, in the PdCu catalyst, Pd remains metallic during reaction, independent of temperature, whereas the Cu oxidizes when the catalyst becomes active, after light-off. Furthermore, DRIFTS studies show that the Cu segregates to the surface as the catalyst becomes active for diesel oxidation, presumably becoming the O2 adsorption site.

Grain refinement induced by grain boundary segregation in FeNiCrCoCu high-entropy alloys using molecular dynamics simulation of nanoindentation

Atomistic simulation of nanoindentation is performed to investigate the effect of Cu segregation at grain boundaries (GBs) on the mechanical properties of FeNiCrCoCu high-entropy alloys. Initially, a combined Monte Carlo and Molecular dynamics simulation technique is adopted to generate the models with Cu segregation, and further the cases of random Cu distribution are considered for the purpose of comparision. The dislocation density, shear strain and GB behavior in the process of nanoindentation are analyzed in detail. The results reveal that the Cu segregation at GBs leads to superiority in hardness, strength, and stiffness. Dislocation analysis shows that the sessile dislocation density is higher at the initial state for the segregation sample, while dislocation nucleation and movements are suppressed so that dislocation-mediated plasticity is weakened. Furthermore, microrotation analysis during the nanoindentation process indicates that segregation of Cu pins the GBs, thereby inhibiting GB rotation and consequently weakening GB-mediated plastic deformation. In this case, grain refinement is observed, and in good agreement with experiment results. Overall, this study provides insights into the influence of GB segregation of Cu on the mechanical properties and deformation response of FeNiCrCoCu HEAs, and highlights the importance of GB composition for tailoring high-strength materials.

Residential Segregation, Perceived Neighborhood Environment, and All-Cause Mortality Among Community-Dwelling Older Chinese Americans.

Residential segregation profoundly affects mental and physical health. However, impacts of residential segregation and other neighborhood characteristics on health among older Asian Americans are not fully understood. This study aimed to close this gap by examining effects of residential segregation, perceived neighborhood cohesion, and neighborhood disorder on all-cause mortality among older Chinese immigrants, as well as testing whether the association between residential segregation and mortality would be mediated by perceived neighborhood cohesion and neighborhood disorder. Data were drawn from a subsample of 3,094 older Chinese Americans aged 60 and older (mean age = 72.8 years) from the Population Study of Chinese Elderly in Chicago. Residential segregation was derived using 2010-2014 American Community Survey data. Participants completed surveys on perceived neighborhood cohesion and neighborhood disorder between 2011 and 2013. All-cause mortality was tracked until December 2021. Residential segregation was associated with elevated all-cause mortality risk; this association, however, was no longer statistically significant after controlling for sociodemographic, behavioral, and health covariates. Perceived neighborhood cohesion, but not neighborhood disorder, was significantly associated with decreased mortality risks. There were no indirect effects of residential segregation on all-cause mortality through perceived neighborhood cohesion or neighborhood disorder. These effects were consistent across male and female participants. These results suggest the importance of neighborhood social environment, specifically perceptions of neighborhood cohesion, in influencing mortality risk among older Chinese immigrants. The findings also indicate the need to conduct further research to examine the health impact of residential segregation among this population.

Segregation mechanism of alloying elements at the fcc-Fe/bcc-Fe interface and its effects on carbon diffusion across the boundary

Understanding the structure and energetics of the fcc/bcc phase interface is essential for lightweight design using advanced high strength steels (AHSSs). The present work investigated the solute segregation and its effects on the interfacial properties of fcc-Fe/bcc-Fe interface utilizing the first-principles calculations. The convergence of fcc-Fe (111) and bcc-Fe (011) slabs was examined, and a 7-layer slab was selected to construct the fcc/bcc interface based on K–S relationship. Then, the segregation behavior of various alloying elements at the interface and the consequent impact on the work of adhesion and interfacial energy were explored. The diffusion behavior of carbon atoms across the interface under the effect of segregation was also investigated. The findings provide theoretical guidance for regulating carbon partitioning via interface engineering and optimizing the design of AHSSs.

A Machine Learning Framework for Quantifying Chemical Segregation and Microstructural Features in Atom Probe Tomography Data.

Atom probe tomography (APT) is ideally suited to characterize and understand the interplay of segregation and microstructure in modern multi-component materials. Yet, the quantitative analysis typically relies on human expertise to define regions of interest. We introduce a computationally efficient, multi-stage machine learning strategy to identify compositionally distinct domains in a semi-automated way, and subsequently quantify their geometric and compositional characteristics. In our algorithmic pipeline, we first coarse-grain the APT data into voxels, collect the composition statistics, and decompose it via clustering in composition space. The composition classification then enables the real-space segmentation via a density-based clustering algorithm, thus revealing the microstructure at voxel resolution. Our approach is demonstrated for a Sm-(Co,Fe)-Zr-Cu alloy. The alloy exhibits two precipitate phases with a plate-like, but intertwined morphology. The primary segmentation is further refined to disentangle these geometrically complex precipitates into individual plate-like parts by an unsupervised approach based on principle component analysis, or a U-Net-based semantic segmentation trained on the former. Following the composition and geometric analysis, detailed composition distribution and segregation effects relative to the predominant plate-like geometry can be readily mapped from the point cloud, without resorting to the voxel compositions.

Effect of solute atoms segregation on Al grain boundary energy and mechanical properties by first-principles study

First-principles calculations were carried out to study the segregation behavior of Mg, and Cu and their effect on the energy and mechanical properties of different Al grain boundaries (GBs). Four symmetrical tilt GBs were selected for study, namely Σ5[001](210) GB, Σ5[001](310) GB, Σ9[110](221) GB, and Σ11[110](332) GB. The results show that both Mg and Cu have a segregation tendency at the GBs, and the segregation tendency of Cu is stronger than Mg. Mg is prone to form substitutional segregation at the GBs, but Cu is more likely to segregate at the interstitial sites. The segregation of Mg and Cu can reduce GB energy, and the GB energy continues to decrease with the increase of the segregation concentration. First-principles calculation tensile test shows that the segregation of Mg has a negative effect on the strength of GBs, and the GB strength decreases with the increase of the Mg concentration, while the GB strength was gradually enhanced with the increase of the Cu concentration. The strength of Σ5(210) GB and Σ9(221) GB are more sensitive to the segregation of solute atoms than the other two GBs. By calculating the charge density and the density of states of the pristine and the segregated GBs, it was found that the segregation of Mg caused charge depletion and structure expansion at the GBs, while the segregation of Cu increases the charge density of GBs and form new bonds with the surrounding Al atoms. The results provide useful information for improving the mechanical properties of materials by using the concept of GB segregation engineering.

On the Temperature-Dependence of Deformation-Induced Martensite Formation in AISI 304L Type Steel

In this study, the deformation-induced α-martensite formation in AISI 304L steel was investigated in the temperature range between 75 °C and − 196 °C in the light of the temperature-dependence of hydrogen embrittlement phenomena. For this purpose, tensile tests with in-situ and ex-situ magnetic measurement of the α-martensite volume content as a function of plastic strain were carried out. In addition, a theoretical assessment of the temperature-dependence of the austenite stability was undertaken, evaluating chemical and non-chemical driving force contributions to the martensitic γ → α transformation as proposed by Ghosh and Olson. The experimental results clearly show an increase in the α-martensite volume content and a shifting of the phase transformation to lower strain levels upon reducing the temperature to − 75 °C. A further reduction of the temperature to − 196 °C revealed to have no significant impact on the α-martensite formation. The theoretical assessments indicate a similar temperature-dependence of the austenite stability as observed experimentally and suggest contributions of the thermal friction work at the fcc/bcc interface to be responsible for a constant austenite stability in low-temperature regimes. Additional investigations of deformed microstructures showed that element segregation effects on the local austenite stability are pronounced around room temperature, but become less relevant at low temperatures.

Revealing the evolution of microstructure and mechanical properties with energy density to achieve high-strength Ti-6wt%Cu alloy by laser metal deposition

In this work, Ti-6wt%Cu alloys were fabricated by laser metal deposition (LMD) technology to understand how the energy densities impact the microstructure and consequent mechanical properties. The results show that a bimodal microstructure of ultrafine eutectoid lamellae and Widmanstätten-α can be obtained at low energy density (118 J/mm3), while higher energy density produces coarse colony-α structure. The multi-scale microstructural refinement is achieved due to the fast cooling rate and low heat accumulation in low energy density deposits, resulting in a sound combination of property with tensile strength of 1063 MPa and elongation of 10%. Based on the solidification theories and accurate solidification parameters in the LMD process, the columnar to equiaxed transition (CET) was proposed to elucidate the refinement mechanism of near-equiaxed prior-β grains. Furthermore, detailed microstructural characterization identified the effect of Cu segregation on the formation of eutectoid lamellae. The Cu aggregation at low energy density plays a crucial role in phase transition and microstructural refinement, as well as account for orientation heterogeneity of lamellae. In addition, the strengthening mechanisms were discussed by considering microstructural evolutions due to different energy densities.

Effect of dynamic recrystallization, LPSO phase, and grain boundary segregation on heterogeneous bimodal microstructure in Mg-9.8Gd-3.5Y-2.0Zn-0.4Zr alloy

The formation conditions and influence mechanisms of the heterogeneous bimodal microstructure of Mg-9.8Gd-3.5Y-2.0Zn-0.4Zr alloy were systematically studied by thermal compression experiments in the range of 0.001–1.0 s−1 and 350–500 °C. Combined with the microstructural characterization, the inherent relationships between the grain structure and the deformation parameters are deeply analyzed. The results indicate that heterogeneous bimodal microstructures composed of fine dynamically recrystallized (DRXed) grains with random orientation and coarsely deformed grains with basal orientation can only be formed under deformation conditions of 40.51 < lnZ < 46.33. This mainly stems from the dominant continuous dynamic recrystallization (CDRX) and particle stimulated nucleation (PSN) mechanisms under this deformation condition. However, dynamic recovery (DRV) and discontinuous dynamic recrystallization (DDRX) dominate isothermal compression process with lnZ > 47.41 and lnZ < 39.74, which eventually lead to unimodal distributions of deformed grains and DRXed grains, respectively. Furthermore, results reveal that deformation parameters have a strong influence on the long-period stacking order (LPSO) phase and grain boundary (GB) segregation. The lamellar LPSO phases and grain boundary co-segregation of Zn, Y, and Gd atoms jointly promote CDRX and inhibit DDRX by preventing GB migration under the condition of 40.51 < lnZ < 46.33, which is ultimately beneficial to the development of heterogeneous bimodal Mg-Gd-Y-Zn-Zr alloy.

Electrochemically Assisted Construction of a La2NiO4+δ@Pt Core-Shell Structure for Enhancing the Performance and Durability of La2NiO4+δ Cathodes.

Ruddlesden-Popper oxide La2NiO4+δ (LNO) has a high ionic conductivity and good thermal match with the electrolyte of solid oxide fuel cells (SOFCs); however, LNO suffers from performance decay owing to the La surface segregation under the operation conditions of SOFCs. Herein, we report an in situ electrochemical decoration strategy to improve the electrocatalytic activity and durability of LNO cathodes. We show that the electrochemical polarization leads to in situ construction of the LNO@Pt core-shell structure, significantly suppressing the detrimental effect of La surface segregation on the LNO cathode. The initial peak power density of a single cell with the LNO cathode is 0.71 W cm-2 at 750 °C, increasing to 1.39 W cm-2 by the in situ construction of the LNO@Pt core-shell structure after polarization at 0.5 A cm-2 for 20 h. The LNO@Pt core-shell structure is also highly durable without noticeable performance degradation over the duration of the test for 180 h. The findings shed light on the design and fabrication of highly active and durable LNO-based cathodes for SOFCs.

Performing up to Nordic principles? Geographic and socioeconomic equity in ambulatory care sensitive conditions among older adults in capital areas of Denmark, Finland and Sweden in 2000–2015

BackgroundDenmark, Finland and Sweden pursue equity in health for their citizens through universal health care. However, it is unclear if these services reach the older adult population equally across different socioeconomic positions or living areas. Thus, we assessed geographic and socioeconomic equity in primary health care (PHC) performance among the older adults in the capital areas of Denmark (Copenhagen), Finland (Helsinki) and Sweden (Stockholm) in 2000–2015. Hospitalisations for ambulatory care sensitive conditions (ACSC) were applied as a proxy for PHC performance.MethodsWe acquired individual level ACSCs for those aged ≥ 45 in 2000–2015 from national hospitalisation registers. To identify whether the disparities varied by age, we applied three age groups (those aged 45–64, 65–75 and ≥ 75). Socioeconomic disparities in ACSCs were described with incidence rate ratios (IRR) and annual rates by education, income and living-alone; and then analysed with biennial concentration indices by income. Geographic disparities were described with biennial ACSC rates by small areas and analysed with two-level Poisson multilevel models. These models provided small area estimates of IRRs of ACSCs in 2000 and their slopes for development over time, between which Pearson correlations were calculated within each capital area. Finally, these models were adjusted for income to distinguish between geographic and socioeconomic disparities.ResultsCopenhagen had the highest IRR of ACSCs among those aged 45–64, and Helsinki among those aged ≥ 75. Over time IRRs decreased among those aged ≥ 45, but only in Helsinki among those aged ≥ 75. All concentration indices slightly favoured the affluent population but in Stockholm were mainly non-significant. Among those aged ≥ 75, Pearson correlations were low in Copenhagen (-0.14; p = 0.424) but high in both Helsinki (-0.74; < 0.001) and Stockholm (-0.62; < 0.001) – with only little change when adjusted for income. Among those aged ≥ 45 the respective correlations were rather similar, except for a strong correlation in Copenhagen (-0.51, 0.001) after income adjustment.ConclusionsWhile socioeconomic disparities in PHC performance persisted among older adults in the three Nordic capital areas, geographic disparities narrowed in both Helsinki and Stockholm but persisted in Copenhagen. Our findings suggest that the Danish PHC incorporated the negative effects of socio-economic segregation to a lesser degree.