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We present new Spitzer/IRS spectra of two hot R Coronae Borealis (RCB) stars,one in the Galaxy,V348 Sgr, and one lying in the LMC, HV 2671. These twoobjects may constitute a link between the RCB stars and the late Wolf-Rayet([WCL]) class of central stars of planetary nebula (CSPNe) such as CPD -56 8032that has little or no hydrogen in their atmospheres. HV 2671 and V348 Sgr aremembers of a rare subclass that has significantly higher effective temperaturesthan most RCB stars, but sharing the traits of hydrogen deficiency and dustformation that define the cooler RCB stars. The [WC] CSPNe star, CPD -56 8032,displays evidence for dual-dust chemistry showing both PAHs and crystallinesilicates in its mid-IR spectrum. HV 2671 shows strong PAH emission but showsno sign of having crystalline silicates. The spectrum of V348 Sgr is verydifferent from those of CPD -56 8032 and HV 2671. The PAH emission seenstrongly in the other two stars is not present. Instead, the spectrum isdominated by a broad emission centered at about 8.2 micron. The mid-IR spectrumof CPD -56 8032 shows emission features that may be associated with C60. Theother two stars do not show evidence for C60. HV 2671 has also been detected byHerschel/PACS and SPIRE. V348 Sgr and CPD -56 8032 have been detected byAKARI/FIS. These data were combined with Spitzer, IRAS, 2MASS and otherphotometry to produce their spectral energy distributions from the visible tothe far-IR. Monte Carlo radiative transfer modeling was used to study thecircumstellar dust around these stars. HV 2671 and CPD -56 8032 require both aflared inner disk with warm dust and an extended diffuse envelope with colddust to to fit their SEDs. The SED of V348 Sgr can be fit with a much smallerdisk and envelope.

The Dust Properties of Two Hot R Coronae Borealis Stars and a Wolf-Rayet Central Star of a Planetary Nebula: in Search of a Possible Link