Iron Implantation Research Articles

Влияние ионной имплантации на свойства чугуна, используемого в конструкциях горнодобывающих машин и аппаратов

Introduction. Cast iron is a widely used material in mechanical engineering, mining and other industries. Modification of the surface properties of cast iron by ion implantation is of great interest. Research methods and materials. Samples of cast iron before and after implantation with C+, B+, N+ ions with dose D = 1017 ions/cm2 and energy of 40 keVwere taken for research. All samples were tested for wear resistance; microhardness was also measured and X-ray analysis was performed. Research results. It is shown that cast iron samples after ion implantation had higher wear resistance and microhardness in comparison with the initial state. The increase in hardness of all samples is apparently associated with the presence of a large number of specific radiation defects and the formation of dispersed phases (nitrides, borides, carbides). Discussion of the research results. The study of micro-hardness was carried out to determine the depth of the hardened layer after ion implantation with C+ , B+ , and N+ ions. The highest micro-hardness was detected at the surface of the sample after irradiation with N + ions. The lowest micro-hardness was obtained by B+ ions. X-ray analysis of cast iron samples after implantation by C+ , B+ , and N+ ions with dose D = 1017 ions/cm2 was the fine structure are observed. Conclusion. Ion implantation of cast iron with C+, B+, N+ ions has shown that irradiation leads to: Increased wear resistance of the material; A significant increase in micro-hardness; Changes in the fine structure of the implanted cast iron (mosaic block size and average dislocation density) and the formation of carbides, borides, and nitrides. Resume. The results of the research show that ion implantation of cast iron can significantly increase the wear resistance of various units of machines (parts) and other mining equipment, which ultimately increases their service life. Suggestions for practical application and direction of future research. The shown results allow us to propose the method of ion implantation as a hardening treatment of parts made of cast iron used, in particular, in the mining industry. In order to develop ion implantation as one of the hardening technologies, it would be advisable to continue studying various physical and chemical properties (for example, corrosion resistance) after exposure to ion implantation.

Physiomimetic biocompatibility evaluation of directly printed degradable porous iron implants using various cell types.

Additively manufactured (AM) degradable porous metallic biomaterials offer unique opportunities for satisfying the design requirements of an ideal bone substitute. Among the currently available biodegradable metals, iron has the highest elastic modulus, meaning that it would benefit the most from porous design. Given the successful preclinical applications of such biomaterials for the treatment of cardiovascular diseases, the moderate compatibility of AM porous iron with osteoblast-like cells, reported in earlier studies, has been surprising. This may be because, as opposed to static in vitro conditions, the biodegradation products of iron in vivo are transported away and excreted. To better mimic the in situ situations of biodegradable biomaterials after implantation, we compared the biodegradation behavior and cytocompatibility of AM porous iron under static conditions to the conditions with dynamic in situ-like fluid flow perfusion in a bioreactor. Furthermore, the compatibility of these scaffolds with four different cell types was evaluated to better understand the implications of these implants for the complex process of natural wound healing. These included endothelial cells, L929 fibroblasts, RAW264.7 macrophage-like cells, and osteoblastic MG-63 cells. The biodegradation rate of the scaffolds was significantly increased in the perfusion bioreactor as compared to static immersion. Under either condition, the compatibility with L929 cells was the best. Moreover, the compatibility with all the cell types was much enhanced under physiomimetic dynamic flow conditions as compared to static biodegradation. Our study highlights the importance of physiomimetic culture conditions and cell type selection when evaluating the cytocompatibility of degradable biomaterials in vitro. STATEMENT OF SIGNIFICANCE: Additively manufactured (AM) degradable porous metals offer unique opportunities for the treatment of large bony defects. Despite the successful preclinical applications of biodegradable iron in the cardiovascular field, the moderate compatibility of AM porous iron with osteoblast-like cells was reported. To better mimic the in vivo condition, we compared the biodegradation behavior and cytocompatibility of AM porous iron under static condition to dynamic perfusion. Furthermore, the compatibility of these scaffolds with various cell types was evaluated to better simulate the process of natural wound healing. Our study suggests that AM porous iron holds great promise for orthopedic applications, while also highlighting the importance of physio-mimetic culture conditions and cell type selection when evaluating the cytocompatibility of degradable biomaterials in vitro.

Implantation of iron into copper: an effective strategy for facilitating electrocatalytic nitrogen reduction reaction

Electrocatalytic nitrogen reduction reaction (ENRR) arises as a potential substitute for the Haber-Bosch approach operated under harsh conditions. Despite numerous research studies on the ENRR, further progress encounters the bottleneck of tough dynamics due to the difficulties in nitrogen activation or protonation. To surmount the obstacle, a simple and effective strategy of iron surface implantation is recommended to modulate the electronic structure of copper electrodeposited on carbon paper for promoting the NRR activity. Owing to iron surface implantation, the Fe/Cu catalyst attains a NH3 yield rate of 6.8 ± 0.4 μg/h/cm and a desirable Faradaic efficiency of 16.0 ± 1.1% in an alkaline electrolyte of 0.1 M KOH. The theoretical calculation results suggest that the implantation of iron can enhance nitrogen adsorption, weaken the N–N σ bond, and lower the energy barrier of the potential determining step to boost the NRR process. This work supplies a new route on designing efficient catalysts for ENRR under ambient conditions.

Comparative Study on Biodegradation of Pure Iron Prepared by Microwave Sintering and Laser Melting.

For biodegradable pure iron implants, a higher biodegradation rate is preferred. In this work, we compared the biodegradation of pure iron prepared by microwave sintering and laser melting (designated as MSed Fe and LMed Fe, respectively). The MSed Fe presented a distinct porous structure, while the LMed Fe presented a relatively compact structure without any obvious pores. The biodegradation rate of the MSed Fe was higher than that of the LMed Fe, and their biodegradation rates were higher than that of the as-cast Fe. The biodegradation rates of the MSed Fe and the LMed Fe were approximately 44 and 13 times higher than that of the as cast Fe, respectively. The biodegradation was closely related to the microstructure’s compactness and grain size. Moreover, the MSed Fe and the LMed Fe had satisfactory biocompatibility.

Local and systemic inflammation after implantation of a novel iron based porous degradable bone replacement material in sheep model

Despite the high potential of healthy bone to regenerate, the reconstruction of large bone defects remains a challenge. Due to the lack of mechanical stability of existing bone substitutes, recently developed degradable metallic alloys are an interesting alternative providing higher load-bearing capabilities. Degradable iron-based alloys therefore might be an attractive innovation. To test the suitability of a newly-designed iron-based alloy for such applications, an animal experiment was performed. Porous iron-based degradable implants with two different densities and a control group were tested. The implants were positioned in the proximal tibia of Merino sheep. Over a period of 6 and 12 months, blood and histological parameters were monitored for signs of inflammation and degradation. In the histological evaluation of the implants` environment we found degraded alloy particles, but no inflammatory reaction. Iron particles were also found within the popliteal lymph nodes on both sides. The serum blood levels of phosphorus, iron and ferritin in the long term groups were elevated. Other parameters did not show any changes. Iron-based degradable porous bone replacement implants showed a good biocompatibility in this experiment. For a clinical application, however, the rate of degradation would have to be significantly increased. Biocompatibility would then have to be re-evaluated.

Degradable silver‐based alloys

AbstractNoble metals solved in iron implants are effective cathodes, which can suit to accelerate the corrosion rate of the base material. In terms of its antibacterial behavior as well as lower costs in comparison with gold or platinum, silver seems to be an attractive candidate to adapt the corrosion rate of implants to the medical requirements. However, the degradation of silver in human bodies is a time‐consuming process, and is controversially discussed due to the unknown long‐term effect of silver on the human organism. Alloying silver with chemical elements less resistant to corrosion in aqueous mediums, particularly, in simulated body fluid, can improve the degradability of silver. Therefore, the current study addresses the design of adapted silver alloys exhibiting improved degradability in comparison with pure silver. Pure silver and binary silver alloys containing silicon, magnesium and calcium are studied in terms of their microstructure, open‐circuit potential and degradation rate.

The Effects of 4%Fe on the Performance of Pure Zinc as Biodegradable Implant Material.

The efforts to develop structural materials for biodegradable metal implants have lately shifted their focus from Magnesium and Iron base alloys towards Zinc. This was mainly due to the accelerated corrosion rate of Mg that is accompanied by hydrogen gas evolution, formation of voluminous iron oxide products with reduced degradation rate in the case of Iron implants and the crucial role of Zn in many physiological processes. However the mechanical properties and degradation capabilities of pure zinc in physiological environment are limited and do not comply with the requirements of biodegradable implants. The present study aims at evaluating the effect of 4%Fe on the in-vitro and in-vivo behavior of pure Zinc. This was carried out in order to address the inherent disadvantages of pure zinc in terms of mechanical properties and biodegradability. The results obtained clearly indicate that the biocompatibility and mechanical properties of the new material system was in accord with the prospective requirements of biodegradable implants. However the corrosion degradation of the new alloy in in-vivo conditions was quite similar to that of pure zinc in spite of the significant micro-galvanic effect created by Delta phase Zn11Fe.

Systemic iron implants alleviate symptoms of Mundulla Yellows in roadside eucalypts in south east South Australia

Mundulla Yellows is a dieback disorder of trees (predominantly eucalypts) along roadsides in the southeast of South Australia, characterized by interveinal yellowing of leaves and eventual death. There are two main theories about the cause of Mundulla Yellows: (1) that the yellowing is lime chlorosis, caused by crushed limestone dust from roads being washed into soil, and (2) that it is caused by an irreversible and transmissible biotic pathogen. We tested the lime chlorosis hypothesis by inserting nutrients directly into the sapwood of symptomatic trees using systemic nutrient implants. If the lime chlorosis hypothesis is correct, nutrient injections of iron and manganese should increase chlorophyll synthesis and result in leaves becoming greener. We applied four different nutrient combinations (iron, manganese, iron + manganese, and a treatment that included a range of essential plant nutrients), as well as control treatments, to symptomatic trees across 10 sites. After 14 weeks there were significant increases in leaf greenness and crown health, compared to controls, when trees received either iron or iron and manganese implants. The results add further weight to the lime chlorosis hypothesis. Nutrient implants are unlikely to be a viable management strategy due to their cost and potentially short-term benefits, and trees will inevitably be lost from the region’s roadsides. Management options should involve increasing revegetation efforts and natural passive regeneration of trees away from affected roadsides, and revegetating the affected areas with species that are suited to the changed soil conditions.

Effect of ion irradiation of the metal matrix on the oxidation rate of Zircaloy-4

The oxidation kinetics acceleration observed in Zircaloy-4 cladding in Pressurized Water Reactor could be partially due to metal irradiation damage occuring in-pile. To check this assumption, several ion irradiation tests of the Zircaloy-4 metal matrix were performed to reproduce the evolution of the metallurgical state in reactor. This study showed that the amorphization process of the intermetallic precipitates (SPPs) does not change significantly the oxidation rate of Zircaloy-4. Implantation of iron in the matrix to simulate iron dissolution from the SPPs has no real impact on the corrosion kinetics. However proton irradiations at 350 °C producing <a> dislocation loops resulted in a significant increase in the oxidation rate.

Implantation of Iron(III) in porphyrinic metal organic frameworks for highly improved photocatalytic performance

Herein a simple approach is proposed to greatly improve the photocatalytic performance of a porphyrinic metal organic framework (PCN-224) by implantation of coordinatively unsaturated Fe(III) sites into the porphyrin unit. Taking the photooxidation of isopropanol (IPA) as a model reaction, the newly developed Fe@PCN-224 exhibits significantly enhanced photocatalytic activity, which is equivalent to an 8.9-fold improvement in acetone evolution rate and 9.3-fold enhancements in CO2 generation rate compared with the PCN-224. Mechanism investigation reveals that the presence of Fe(III) sites in the PCN-224 can not only greatly boost the electron–hole separation efficiency, but also effectively convert the in-situ photogenerated inactive H2O2 into reactive oxygen-related radicals via Fenton reactions to participate in the photocatalytic IPA oxidation. The enhanced photocatalytic activity for IPA oxidation is also observed over another Fe(III) implanted porphyrinic metal organic framework (Fe@PCN-222), suggesting the generality of this strategy.

Systemic Assessment of Calcium and Phosphorus Level after Implantation of Porous Iron in Rats

One of important aspects in bone healing process is physiological level of calcium (Ca), and phosphorus (P) that can be altered by implantation of biodegradable porous iron. Therefore, this study aims to investigate the concentration of Ca, P and Ca/P ratio in the peripheral blood during the implantation period up to 4 months. Forty adult male Sprague Dawley rats were used and divided into 3 groups receiving different pore size of iron implants (pore size 450, 580, 800μm) and one group of sham. The implants (5x2x0.5mm) were inserted into flat bone defects at latero-medial of femoral bone. Blood sample was taken from ventral tail artery before and after 4 month of implantation. Calcium and P concentrations in the blood were determined by BA-88A Semi-Auto Chemistry Analyzer. Results showed that concentration of Ca and P are slightly higher after implantation than before implantation, except for the 450μm group. The Ca/P ratio before and after implantation was increased in the sham group, and decreased in the 450 and 800μm groups. Concentration of Ca, P and Ca/P ratio insignificantly change between before and 4 months after surgery in some groups.

Synthesis of magnetic nanoparticles by low-energy dual ion implantation of iron and nickel into silicon dioxide followed by electron beam annealing

Magnetic nanoparticles have been made by low-energy dual ion implantation of iron and nickel into SiO2 with a nickel fluence ratio of 82% followed by electron beam annealing for 1800 s at 1000°C. After annealing, there is significant diffusion of iron and nickel into the silicon dioxide layer. Annealing also led to the formation of superparamagnetic nanoparticles with a narrow particle size distribution. The saturation moment at 5 K was 0.7 µB and a similar value was observed at 300 K, which indicates that the Curie temperature is far above room temperature. This moment is lower than that expected for Ni0.82Fe0.18. While the results clearly show the formation of superparamagnetic nanoparticles, it is not possible to determine whether nickel-iron, iron or nickel has formed.

Local and systemic analysis of porous iron implantation in femoral bone of rats

Event Abstract Back to Event Local and systemic analysis of porous iron implantation in femoral bone of rats Mokhamad Fakhrul Ulum1, Devi Paramitha1, 2, Sitaria Fransiska Siallagan1, Arlita Sariningrum1, Anizza Dyah Kartika Maharani1, Fitri Aprian Harjo1, Muhammad Fajar Nashrulloh1, Risti Laily1, Dwida Rahmadani1, Retno Wulansari1, Hera Maheshwari1, Hendra Hermawan2 and Deni Noviana1 1 Bogor Agricultural University, Faculty of Veterinary Medicine, Indonesia 2 Laval University, Department of Mining, Metallurgical and Materials Engineering & CHU de Quebec Research Center, Canada Introduction: Recently porous biodegradable metals have been proposed as new materials for bone scaffolds [1] with magnesium as the most studied over the last 5 years [2]. Its porous structure was proven to play important role in cell growth, spreading and proliferation due to higher surface contact area and interconnectivity within the pores [3]. Meanwhile, porous iron is introduced more recently [4] where in vitro cytotoxicity assessments show positive effect toward the proliferation of mesenchymal and osteoblast cells [4],[5]. In this work we aim to further elaborate its potentiality as bone implant material via in vivo implantation study in femoral bone of rats and evaluation of the local and systemic body response. Materials and Methods: This study was approved by Animal Care and Use Committee, Bogor Agricultural University (#6-2014 IPB). Implants (5 x 2 x 0.5 mm3) were prepared form pure porous iron (Alantum, Korea) with with pore size of 450 μm, 580 μm, and 800 μm. Sixty male Sprague Dawley rats (6-7 weeks age) were grouped based on the implant’s pore size and 1 sham group. Implants were inserted into the right femur bone defects. Local and systemic body responses were observed at day 7, 14, and 30 post-implantation (n=5). One mL of venous-tail blood was collected and analysed for cell blood count, biochemistry profile, and concentration of metal (Fe, Ca, P) ions. Peri-implant muscle samples were collected at near (±0.1 mm) and far (±5 mm) areas from implant for Fe ion concentration analysis. Radiograms were taken using portable digital computer radiography. Colorimetric analysis was done on retrieved implants and on opened area of implant-tissue contact using image analysis software. All data were statistically analyzed using one way ANOVA and Duncan test. Results and Discussion: Fig. 1A presents evidence that porous iron implant only affect the percentage of neutrophil, lymphocyte, and monocyte due to the inflammation response against the implant [6]. The concentration of Fe and Ca ions was increase in the 1st weeks of implantation (Fig 1B) similar to our previous findings [7]. Fig. 1C shows the changes of kidney and liver enzyme function in the level of SGPT, SGOT, urea, and creatinine over time. Fig. 1. Systemic blood profile analysis. (A) Cells blood count, (B1-3) Metal (Fe, Ca, and P) ion concentration, (C1-4) Liver and renal enzyme function biochemistry. Fig. 2A shows radiograms with different degradation rate of the implants due to different pore size. However, there is no significant difference in term of peri-implant-bone radio-density and pore sizes (Fig. 2B). Iron ion concentration was found higher at the near peri-implant area and was decreasing over 30 days, except for the 800 μm group (Fig. 2C). Fig. 2. Radiograms and local Fe ion analysis: (A1-3) Radiography at day 30, (B1-3) Radiodensity of implant, peri-implant-bone and peri-implant-muscles, (C1-3) Fe ions concentration at local tissue. Fig. 3A shows that the colorimetric analysis on the opened peri-implant tissue and the retrieved implant has consistently with the radiographic analysis. The reddish-brown tissue intensity is higher for 450 μm implant group (Fig. 3B). This can be related to higher volume of iron in this group and the greater implant-tissue interaction area causing pronounce earlier degradation process[8]. Fig. 3. Colorimetric image analysis of: (A1-4) Opened peri-implant tissue, (B1-4) retrieved implant and its corrosion product. Conclusions: In general, the study provide evidences that the implantation of porous iron implants on the femoral bone of rats does not cause negative effect toward local and systemic biological responses of the animal. The authors acknowledge Indonesian Ministry of Education and Culture-DGHE for grant No. 083/SP2H/PL/Dit.Litabmas/II/2015 and the collaboration with Alantum, Korea, and CHU de Quebec Research Center, Laval University.; This work in part of the international Indonesia-Canada collaboration between Laval University and Bogor Agricultural University.; The authors thank to Dr. Erwin, Dr. Sitaria Fransiska Siallagan, Dr. Tetty Barunawati Siagian, Dr. Frizky Amelia and Dr. Nindya Dwi Utami for the discussion.

Influence of Surface Nanocrystallization on Ti Ion Implantation of Pure Iron

In order to increase the depth or concentration of Ti ion implantation of pure iron, the surface mechanical attrition treatment (SMAT), which can fabricate a nanometer-grained surface layer without porosity and contamination in a pure iron plate, was used before ion implantation. Ti ion was implanted into the SMA treated sample and coarse-grained counterpart by using a metal vapor vacuum arc source implanter. The changing of depth and concentration of Ti was studied in a function of implantation time. By optical microscopy, transmission electron microscopy and X-ray diffraction, the grain size of the nano structured surface was studied. Micro-hardness, friction and wear behavior of nano surface layers were studied. By energy dispersive X-ray spectroscopy and Auger electron spectroscopy, the chemical composition and concentration of Ti ion in the surface implantation layer were studied. Experimental results showed that the concentration of Ti increased dramatically compared with untreated coarse-grained samples, which is attributed to the existence of higher density of defects (supersaturated vacancies, dislocations, non-equilibrium grain boundaries etc.) and compression stress field in the SMA treated nanocrystallined surface layer. The interaction between the defects and the implanted solute atoms leads to the increment of solid solubility. But the implantation depth showed inconspicuous change. It is shown that the ion range is just relevant to the energy and mass of the ion, dose of injection, the mass and density of target material.

Cavity nucleation and growth during helium implantation and neutron irradiation of Fe and steel

The present work concerns investigations of damage accumulation during helium implantation of pure iron and the reduced activation ferritic-martensitic steel 'EUROFER 97' at 323K and 623K as well as during neutron irradiation with or without prior helium implantation. The defect microstructure, in particular the cavities, was characterized using Positron Annihilation Lifetime Spectroscopy (PALS) and Transmission Electron Microscopy (TEM). The PALS investigations reveal a clear difference between the He implantation effects in Fe and EUROFER 97 at both temperatures. For both materials the mean positron lifetime increases with He dose in the range 1 – 100 appm, although the increase is stronger for Fe than for EUROFER 97 and for both materials stronger for implantation at 323K than at 623K.

Mössbauer study of the magnetic phase composition of single-crystalline rutile (TiO2) implanted with iron ions

Depth-resolved Mossbauer measurements have been performed for four ferromagnetic samples obtained by the implantation of iron ions (enriched to ∼ 50% with 57Fe isotope) into single-crystalline rutile (TiO2) substrates with two crystallographic orientations [(100) and (001)] at different temperatures (300 and 900 K). It is established that the ferromagnetic properties of iron-implanted rutile samples at room temperature are determined by the presence of α-Fe and Fe3O4 phases. The phase composition of samples obtained by iron implantation into substrates heated to 900 K depends on the crystallographic orientation of the substrate, which is explained by a significant anisotropy of the diffusion of iron atoms in rutile.

Comparison of the damage in sapphire due to implantation of boron, nitrogen, and iron

The damage microstructure and optical properties of sapphire implanted with boron, nitrogen and iron were examined by RBS-C, TEM, and optical absorption. Implantations were conducted at RT and 1000 °C at 150 keV and fluences of 3 × 10 16–1 × 10 17 ions/cm 2. Optical absorption measurements indicate that the boron-implanted samples contained the highest number of F-type centers and the nitrogen-implanted samples the fewest. The microstructure of the boron-implanted samples shows only ‘black-spot’ defect clusters, as did the iron-implanted samples at the lower fluences. At higher fluences, the iron implanted samples revealed the presence of nanometer-sized precipitates of single crystal bcc iron that contributed to additional optical scattering. Bubbles formed in samples implanted with low fluences of nitrogen. A second damage region is apparent in the RBS-C patterns for higher fluences of nitrogen.

Electronically-coupled up-conversion: an alternative approach to impurity photovoltaics in crystalline silicon

The traditional approach to harnessing the impurity-photovoltaic effect to improve solar cell performance is plagued by additional recombination caused by the impurity centres. This extra recombination channel is usually deemed to outweigh the benefits of additional generation of electron–hole pairs via sub-band-gap absorption through the impurity levels. Here we consider an alternative approach that restricts the impurity levels to a film with a wider band gap at the rear of a solar cell, isolating the impurities from the minority carriers generated in the base, but, in principle, still allowing impurity-generated carriers to contribute to the cell current. Initial proof-of-concept experiments show that implantation of silicon ions into amorphous silicon films on the rear of crystalline silicon wafers results in the desired increase in sub-band-gap absorptance of infrared photons, without degrading the surface passivation properties of the amorphous layer. However, these defect states are not thermally stable, and in any case do not result in additional carriers being injected into the silicon wafer itself, either because the infrared-generated carriers relax back to the valence band before the second photon can be absorbed, or because the free carriers recombine before reaching the wafer interface. Subsequent attempts involving implantation of iron and erbium impurities to generate stable absorption centres in the amorphous silicon films also failed to inject additional carriers into the crystalline wafer. Possible modifications that may alleviate these problems are discussed.

Magnetic Properties of Thin Metal-Polymer Films Prepared by High-Dose Ion-Beam Implantation of Iron and Cobalt Ions into Polyethylene Terephthalate

Thin metal-polymer composite films have been prepared by high-dose ion-beam implantation of Fe+ and Co+ ions into polyethylene terephthalate. The implantation of 40 keV ions at room temperature with doses from 2 · 1016 to 4 · 1017 cm−2 have been performed, with the ion current density of 4 μA/cm2. The effects of implantation dose on the film morphology and crystal structure have been investigated via atomic force and magnetic force microscopy and X-ray diffraction. The magnetic properties of synthesized structures have been studied by ferromagnetic resonance and with a vibrating-sample magnetometer. It was established that the properties of ion-implanted samples strongly depend on both the implantation dose and the type of implanted ions. The implantation dose at which the magnetic phase is formed for iron-implanted samples is significantly lower than that for cobalt-implanted ones. At high implantation doses due to polymer sputtering metal-containing layers are formed close to the sample surface for both ions. In this dose range the magnetic properties of implanted samples changed dramatically due to particle oxidation. The coercivity of synthesized layers reaches 180 and 300 Oe for iron- and cobalt-implanted samples, respectively.

The influence of iron, fluorine and boron implantation on the magnetic properties of graphite

Iron, fluorine and boron ions were implanted into highly oriented pyrolytic graphite (HOPG). The samples were characterized before and after ion implantation as well as after heat treatments in vacuum by measurements of the magnetic moment and element analysis. Whereas the main magnetic contribution remains diamagnetic the paramagnetic one clearly increases with implantations and correlates with the amount of implanted ions. It is shown that a large part of the paramagnetic contribution is caused by the structural disorder created by particle bombardment using iron, fluorine or boron. All implanted HOPG samples show practically no change of the small ferromagnetic signal observed in their virgin state. No particular influence of iron on the ferromagnetic properties of HOPG is observed, up to ∼4000 μg/g Fe-concentration in the implanted region. For comparison, ferrous sulphates were added to ultra-clean graphite powder. This iron addition increases the number of paramagnetic spins proportional to the iron content in the untreated samples. In heat-treated samples however, a clear ferromagnetic behaviour is observed due to the formation of a ferromagnetic iron compound.